Slide woman under narrow opening (7)
I believe the answer is:
slither
'slide' is the definition.
(I know that slide can be written as slither)
'woman under narrow opening' is the wordplay.
'woman' becomes 'her' (her refers to a woman).
'under' is a charade indicator (letters next to each other) (below, in a down clue).
'narrow opening' becomes 'slit' (I've seen this before).
'her' after 'slit' is 'SLITHER'.
(Other definitions for slither that I've seen before include "Move like a snake" , "Slide on slippery surface" , "Slide unsteadily" , "Slide (like a snake)" , "Slide, slip" .)