Source : Webster's Revised Unabridged Dictionary (1913)

Tense \Tense\, a. [L. tensus, p. p. of tendere to stretch. See
   {Tend} to move, and cf. {Toise}.]
   Stretched tightly; strained to stiffness; rigid; not lax; as,
   a tense fiber.

         The temples were sunk, her forehead was tense, and a
         fatal paleness was upon her.             --Goldsmith.
   -- {Tense"ly}, adv. -- {Tense"ness}, n.

Source : WordNet®

tenseness
     n 1: the physical condition of being stretched or strained; "it
          places great tension on the leg muscles"; "he could feel
          the tenseness of her body" [syn: {tension}, {tensity}, {tautness}]
     2: (psychology) a state of mental or emotional strain or
        suspense; "he suffered from fatigue and emotional
        tension"; "stress is a vasoconstrictor" [syn: {tension}, {stress}]