Definitions of tense:

• noun:   a grammatical category of verbs used to express distinctions of time
• verb:   make tense and uneasy or nervous or anxious;
• verb:   become tense or tenser

  Example: "He tensed up when he saw his opponent enter the room"

• verb:   increase the tension on

  Example: "Tense a rope"

• verb:   stretch or force to the limit
• adjective:   taut or rigid; stretched tight

  Example: "Tense piano strings"

• adjective:   pronounced with relatively tense tongue muscles (e.g., the vowel sound in `beat')
• adjective:   in or of a state of physical or nervous tension