The Collaborative International Dictionary of English v.0.48:

Unmanly \Unmanly\
   See manly.

WordNet (r) 3.0 (2006):

unmanly
    adv 1: without qualities thought to befit a man [syn:
           unmanfully, unmanly] [ant: manfully, manly]
    adj 1: not possessing qualities befitting a man [syn: unmanly,
           unmanful, unmanlike] [ant: manful, manlike,
           manly]
    2: lacking in courage and manly strength and resolution;
       contemptibly fearful [syn: pusillanimous, poor-spirited,
       unmanly]

Moby Thesaurus II by Grady Ward, 1.0:

48 Moby Thesaurus words for "unmanly":
   afraid, chicken, chickenhearted, coward, cowardly, cowed, craven,
   daunted, dismayed, effeminate, epicene, fainthearted, fearful,
   funking, funky, gutless, henhearted, intimidated, lily-livered,
   milk-livered, milksoppish, milksoppy, mousy, muliebrous,
   old-womanish, overtimid, overtimorous, panic-prone, panicky,
   pigeonhearted, poltroon, prissy, pusillanimous, rabbity, sissified,
   sissy, sissyish, soft, spunkless, timid, timorous, unmanned, weak,
   weak-kneed, weakhearted, white-livered, womanish, yellow