The desire of a woolly-headed six-footer (4)
I believe the answer is:
want
'the desire' is the definition.
(want is a kind of desire)
'a woolly-headed six-footer' is the wordplay.
'a woolly-headed' becomes 'w' (this could be a standard abbreviation of which I'm unaware).
'six footer' becomes 'ant'.
'w'+'ant'='WANT'
'of' acts as a link.
Can you help me to learn more?
(Other definitions for want that I've seen before include "Need or desire" , "Desire - deficiency" , "'Wilful waste makes woeful . . . .'" , "Wish" , "Lack, desire" .)