He goes round the bend a shade (3)
I believe the answer is:
hue
'a shade' is the definition.
(both can mean a colour)
'he goes round the bend' is the wordplay.
'goes round' is an insertion indicator.
'the bend' becomes 'U' (a U-bend is a kind of bend - pipe under sink).
'he' placed around 'u' is 'HUE'.
(Other definitions for hue that I've seen before include "appearance" , "Colour or tint" , "General hubbub - . . . and cry" , "General outburst of alarm or protest - . . . and cry" , "Shade, aspect; Vietnam port" .)