2 letters:
up

3 letters:
cup, pup, sup, yup

5 letters:
do up, getup, go up, krupp, letup, pinup, setup, shtup

6 letters:
act up, add up, backup, blowup, bob up, box up, burnup, buy up, cockup, cut up, dam up, dig up, dry up, dustup, eat up, eggcup, end up, eyecup, fed up, fig up, fix up, fog up, gas up, get-up, get up, gum up, holdup, hookup, hop up, hot up, ice up, kickup, kit up, lap up, lay-up, lay up, let up, lineup, linkup, lockup, log up, makeup, markup, mat up, mix-up, mix up, mop up, mug up, pal up, pay up, pen up, pep up, pickup, pileup, pin-up, pin up, pop-up, pop up, pushup, put-up, put up, rev up, rig up, rip up, rub up, run-up, run up, selkup, sendup, set-up, set up, sit-up, sit up, slipup, sop up, sum up, tcp ip, teacup, tee up, tie-up, tie up, tip-up, tittup, tossup, tot up, turnup, use up, washup, wickup, windup, zip up

7 letters:
ante up, back-up, back up, ball up, bang-up, bang up, bear up, beat-up, beat up, beef up, belt up, blow up, bomb up, bone up, book up, breakup, brushup, buck up, buildup, bump up, buoy up, burn up, bust-up, bust up, call-up, call up, chat up, checkup, chew up, chin-up, chin up, chop up, chum up, clam up, clap up, cleanup, clog up, closeup, cock-up, cock up, come up, cook up, coop up, cork up, coverup, cozy up, crap up, crop up, curl up, deck up, dial-up, dish up, doll up, dope up, drag up, draw up, drum up, ease up, edge up, egg cup, elf cup, even up, eye cup, face up, felt up, fill up, fire up, firm up, fold up, fort up, foul-up, foul up, gang up, gear up, give up, goldcup, grownup, grow up, grub up, hang-up, hang up, hard up, haul up, head up, heap up, heat up, heft up, high-up, high up, hike up, hive up, hold up, hole up, hook up, hush up, hype up, jack up, jazz up, keep up, kept up, kick up, kingcup, lace up, land up, lash-up, lead up, lift up, line-up, line up, load up, lock up, look up, made-up, make-up, make up, mark up, mess-up, mess up, mock-up, mock up, move up, muck up, nosh-up, open up, paid-up, pass up, pent-up, perk up, pick-up, pick up, pile up, pipe up, piss-up, play up, pony up, prim up, prop up, puff up, pull-up, pull up, push-up, push up, rack up, rake up, rave-up, ring up, rise up, roll-up, roll up, roundup, rout up, ruck up, sack up, save up, sell up, shakeup, show up, shut up, sign up, silt up, size up, slap-up, slip-up, slip up, slow up, snap up, soak up, soar up, soup up, speedup, spit up, standup, startup, stay up, step-up, step up, stickup, stir up, stop up, suck up, take-up, take up, tart up, team up, tear up, tidy up, tone up, toss-up, tote up, trip up, true up, tune-up, tune up, turn up, used-up, used up, vamp up, wake up, walk-up, wall up, warm-up, warm up, wash up, well up, went up, whip up, wickiup, wind-up, wind up, wipe up, wise up, work up, wrap up

8 letters:
balls-up, belly-up, blaze up, block up, blown-up, blown up, board up, boost up, booze-up, botch up, bound up, brace up, break up, brick up, bring up, brisk up, brush up, build up, built-up, bunch up, carve up, catch up, chain up, chalk up, cheer up, chock up, choke up, churn up, clean up, clear up, climb up, clock up, close-up, close up, cloud up, cough up, cover-up, cover up, crack-up, crack up, crank up, creep up, crock up, dice cup, divvy up, dream up, dress up, dried-up, drink up, drive up, dummy up, earth up, eaten up, fancy up, fetch up, flame up, flare-up, flare up, fluff up, followup, frame-up, frame up, grown-up, gussy up, heads-up, heave up, hitch up, jolly up, juice up, knock up, light up, liven up, louse up, mixed-up, mount up, muddy up, offer up, paste-up, patch up, plump up, point up, press-up, prick up, psych up, punch-up, queue up, raise up, rough up, round up, saved up, scale up, scoop up, screw up, scrub up, serve up, seven-up, shack up, shake-up, shake up, shape-up, shape up, shine up, shoot up, shore up, sidle up, slack up, slice up, slick up, smash up, smell up, snarl-up, snarl up, sneak up, sober up, speak up, spear up, speed up, spice up, split up, stack up, stand-up, stand up, start-up, start up, stick up, stink up, stuck-up, sweep up, swell up, swoop up, taken up, tense up, think up, throw up, touch up, trice up, trick up, trump up, tying up, using up, vomit up, whitecup, wolf pup, wound up, write-up, write up, yield up

9 letters:
acorn cup, backed up, beaten-up, beefed-up, blood cup, bottle up, bottom-up, bridle up, brown cup, bubble up, bucked up, bundle up, buttercup, butter up, button up, change-up, charge up, choose up, cobble up, cotton up, couple up, curled up, death cup, dixie cup, doctor up, dolled up, double up, dredge up, drying up, fairy cup, fatten up, finish up, follow-up, fucked-up, gather up, ginger up, giving up, gobble up, grace cup, heaped-up, heated up, higher-up, higher up, hit it up, hopped-up, jumped-up, limber up, loosen up, marked-up, muster up, optic cup, paper cup, perked up, polish up, pretty up, pumped-up, pumped up, rolled-up, ruffle up, runner-up, scrape up, snatch up, spirit up, sponge up, spring up, spruce up, square up, stored up, strike up, string up, sweet cup, waking up, washed-up

10 letters:
blowing up, bolster up, bristle up, churned-up, clutter up, coffee cup, conjure up, digging up, divided up, dressed-up, fancied up, freshen up, furbish up, golden cup, gussied up, lighten up, live it up, loving cup, measure up, pick-me-up, scratch up, scrunch up, shoring up, shrivel up, soaking up, speeded up, spruced up, stirred up, stopped-up, stopped up, summing up, swallow up, tighten up, trumped-up, washing-up, wrapped up

11 letters:
bringing up, clouding up, coughing up, painted cup, propping up, puckered-up, queen's cup, scarlet cup, stirrup cup, whoop it up

12 letters:
drinking cup, mustache cup, trash pickup

13 letters:
champagne cup, drain the cup, measuring cup, moustache cup, straighten up

14 letters:
black felt cup, crystal pickup, garbage pickup, johnny-jump-up, tall buttercup

15 letters:
computer backup, giant buttercup, medical checkup, water buttercup

16 letters:
common buttercup, meadow buttercup, temporary hookup

17 letters:
bermuda buttercup, western buttercup

18 letters:
creeping buttercup

19 letters:
charred pancake cup, sagebrush buttercup

20 letters:
tall field buttercup