Antonym of relax

Antonyms of verb relax

2 of 8 senses of relax

Sense 1:

relax, loosen up, unbend, unwind, decompress, slow down
Antonym of tense (Sense 3)
=>tense, tense up

Sense 4:

relax, unstrain, unlax, loosen up, unwind, make relaxed
Antonym of tense (Sense 4)
=>tense, strain, tense up