unassertive -
inclined to timidity or lack of self-confidence; "a shy unassertive person"
assertive,
self-asserting,
self-assertive aggressively self-assured; "an energetic assertive boy who was always ready to argue"; "pointing directly at a listener is an assertive act"
submissive inclined or willing to submit to orders or wishes of others or showing such inclination; "submissive servants"; "a submissive reply"; "replacing troublemakers with more submissive people"
