Unassumingly (8)
I believe the answer is:
modestly
'unassumingly' is the definition.
(I've seen this before)
This is all the clue.
(Other definitions for modestly that I've seen before include "With humility" , "Unassumingly" , "In an unassuming, unpretentious way" , "Fairly" , "In demure fashion" .)