--- on the back, hearty congratulation (4)
I believe the answer is:
slap
(Other definitions for slap that I've seen before include "Strike with the palm" , "Sharp smack" , "Blow with open hand" , "A blow among pals" , "Hit with an open hand" .)
I believe the answer is:
slap
(Other definitions for slap that I've seen before include "Strike with the palm" , "Sharp smack" , "Blow with open hand" , "A blow among pals" , "Hit with an open hand" .)