Not arrogant or presuming:
— A shy retiring girl.

synonym: unassuming.

Roget 252: depressed etc. v.; alveolate^†, calathiform^†, cup-shaped, dishing; favaginous^†, faveolate^†, favose^†; scyphiform^†, scyphose^†; concave, hollow, stove in; retiring; retreating; cavernous; porous etc. (with holes) 260; infundibul^†, infundibular^†, infundibuliform^†; funnel shaped, bell shaped; campaniform^†, capsular; vaulted, arched.    ... show more

Roget 438: blue, azure, cerulean; sky-blue, sky-colored, sky-dyed; cerulescent^†; powder blue, bluish; atmospheric, retiring; cold.   

Of a person who has held and relinquished a position or office:
— A retiring member of the board.

synonyms: past, preceding.

Reluctant to draw attention to yourself.

synonyms: reticent, self-effacing.