Some hesitation over bikini top’s shade (5)
I believe the answer is:
umbra
'shade' is the definition.
(I know that umbra is a type of shadow)
'some hesitation over bikini top's' is the wordplay.
'some hesitation' becomes 'um' (um is said in hesitation).
'over' is a charade indicator (letters next to each other).
'bikini top' becomes 'bra' (a bra is part of a bikini).
'um'+'bra'='UMBRA'
(Other definitions for umbra that I've seen before include "Dark region" , "Deep shadow" , "shady region" , "Shadow's inner region" , "Rumba (anag.)" .)