Snappy son with little yen to show gesture of respect (6)
I believe the answer is:
curtsy
'gesture of respect' is the definition.
(I've seen this in another clue)
'snappy son with little yen' is the wordplay.
'snappy' becomes 'curt' (I've seen this before).
'son' becomes 's' (genealogical abbreviation for son).
'with' is a charade indicator (letters next to each other).
'little' suggests taking the first letters.
The first letter of 'yen' is 'y'.
'curt'+'s'+'y'='CURTSY'
'to show' is the link.
(Other definitions for curtsy that I've seen before include "Bend the knees in a gesture of respect" , "Kind of respectful bob made by women" , "Gesture of respect by women" , "Bend the knee in respect" , "Woman's formal greeting" .)