Bow put on upside down (3)
I believe the answer is:
nod
'bow' is the definition.
(I have seen 'slight bow' mean 'nod' so perhaps 'bow' could also mean 'nod')
'put on upside down' is the wordplay.
'put on' becomes 'don' ('don' can be a synonym of 'put on').
'upside down' says the letters should be written backwards.
'don' backwards is 'NOD'.
(Other definitions for nod that I've seen before include "The Land of ... lay east of Eden" , "Signify assent" , "Gesture; agree" , "Sign of agreement" , "Careless mistake" .)