WordNet (r) 3.0 (2006):

uptight
    adj 1: being in a tense state [syn: edgy, high-strung,
           highly strung, jittery, jumpy, nervy,
           overstrung, restive, uptight]

Moby Thesaurus II by Grady Ward, 1.0:

33 Moby Thesaurus words for "uptight":
   accordant, anal, bourgeois, compulsive, concordant, conformist,
   conventional, corresponding, edgy, formalistic, harmonious,
   in accord, in keeping, in line, in step, kosher, nervy, orthodox,
   pedantic, plastic, precisianistic, restive, square, straight,
   strained, stretched tight, stuffy, taut, tense, traditionalist,
   under a strain, uneasy, unrelaxed