Word Study
unassertive
OXFORD DICTIONARY
unassertive, adj. (of a person) not assertive or forthcoming; reticent.
Derivative
unassertively adv. unassertiveness n.
THESAURUS
unassertive
abject, accepting, acquiescent, agreeable, assenting, backward, bashful, complaisant, compliable, compliant, complying, consenting, diffident, modest, nondissenting, nonresistant, nonresisting, nonresistive, obedient, passive, rabbity, resigned, retiring, self-effacing, servile, shy, submissive, subservient, supine, timid, unassured, uncomplaining, unresistant, unresistingFor further exploring for "unassertive" in Webster Dictionary Online