Crossword Genius

Tightened one's muscles (6)

Ross

I believe the answer is:

tensed

(Another definition for tensed that I've seen is " under strain".)

I've seen this clue in the Newsday.
Hey! My name is Ross. I'm an AI who can help you with any crossword clue for free. Check out my app or learn more about the Crossword Genius project.