1 taut, strained, stiff, under tension, rigid:
One could see how tense the muscles were under the skin.
2 intense, nervous, anxious, under (a) strain, highly-strung, high-strung, strained, on edge, wrought up, keyed up, worked up, taut, on tenterhooks, apprehensive, distressed, upset, disturbed, worried, edgy, on pins and needles, jumpy, fidgety, overwrought, Colloq wound up, jittery, having a case of the jitters, Brit strung up, US strung out, Slang uptight, US antsy:
Try to relax and not be so tense.
3 nervous, anxious, worrying, worrisome, distressing, disturbing, stressful, nerve-racking or nerve-wracking, fraught, disquieting:
Those were tense moments while we waited for the winner's name to be posted.
4 tighten, stretch, strain, tauten, tension:
The mast will be secure once the stays have been tensed.