Open wide to swallow a bit of ripe fruit (5)
I believe the answer is:
grape
'fruit' is the definition.
(grape is a kind of fruit)
'open wide to swallow a bit of ripe' is the wordplay.
'open wide' becomes 'gape' (I've seen this before).
'to swallow' means one lot of letters goes inside another.
'a bit of' says to take the initial letters.
The first letter of 'ripe' is 'r'.
'gape' placed around 'r' is 'GRAPE'.
(Other definitions for grape that I've seen before include "Pager (anag.)" , "Wine fruit" , "In Elgin rummage about in the dark" , "Vine fruit" , "Fruit from bunch" .)