tense

[1]	strain
[2]	tighten , tense up , stretch , strain , tauten , tension
[3]	strain , tense up

adj.

[1]	taut , strained , stiff , under tension , rigid
[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
[3]	nervous , anxious , worrying , worrisome , distressing , disturbing , stressful , nerve-racking/nerve-wracking , fraught , disquieting