Show appreciation of cold drink (4)
I believe the answer is:
clap
'show appreciation of' is the definition.
(as in applause)
'cold drink' is the wordplay.
'cold' becomes 'c' (eg on taps).
'drink' becomes 'lap' (to lap is to drink).
'c'+'lap'='CLAP'
(Other definitions for clap that I've seen before include "A meeting of hands" , "cheer" , "Strike hands together to applaud" , "Make sound of applause" , "Sudden loud noise (of thunder?)" .)