angular, gawky, lubberly, ungainly

boorish, clownish, uncouth

abashed, discomfited, discomforted, discomposed, disconcerted, discountenanced, embarrassed

self-conscious

agitated, bothered, chagrined, dismayed, disquieted, distressed, disturbed, fazed, flustered, jittery, jumpy, mortified, nervous, nonplussed (also nonplused), perturbed, rattled, unhinged, unsettled, upset

diffident, insecure, meek, modest, self-doubting, timid, unassertive, unassuming, unpretentious