retiring

not blatant or overly aggressive in manner or appearance

• “a retiring disposition”

moving toward a position farther from the front

• “the receding glaciers of the last ice age”
• “retiring fogs revealed the rocky coastline”

not arrogant or presuming

• “unassuming to a fault, skeptical about the value of his work”
• “a shy retiring girl”

of a person who has held and relinquished a position or office

• “a retiring member of the board”