(especially of a woman) quiet and serious

reserved, affected

not having, not showing, much belief in one's own abilities

hesitant; unconfident

(of a person) feeling doubt

doubtful

not safe; not providing good support; not to be relied on

uncertain, worried

having, showing, a low but honest opinion of one's own merits, abilities etc; not large in size or amount

shy

(of a person) self-conscious and uncomfortable in the presence of others; (of animals etc) easily frightened

quiet and self-conscious

easily frightened

shy

not confident; not certain or reliable

doubtful, insecure

not trustworthy

not dependable, unfaithful