Right hand coming in low grasped retreating American ladies (8)
I believe the answer is:
washroom
'american ladies' is the definition.
(US term for a toilet - eg the ladies)
'right hand coming in low grasped retreating' is the wordplay.
'right hand' becomes 'RH' (medical abbreviation).
'coming in' is an insertion indicator.
'low' becomes 'moo' (both can mean to make the noise of a cow).
'grasped' becomes 'saw' (grasp can mean to see or apprehend).
'retreating' is a reversal indicator.
'moo'+'saw'='moosaw'
'rh' going inside 'moosaw' is 'moorhsaw'.
'moorhsaw' backwards is 'WASHROOM'.
(Other definitions for washroom that I've seen before include "Where Americans go" , "bog across the pond" , "US loo" , "Clean up place" .)