A title some desire (3)
I believe the answer is:
sir
'a title' is the definition.
(respectful address for a man)
'some desire' is the wordplay.
'some' says the answer is hidden in the clue (some of the parts of the word are used).
'SIR' can be found hidden inside 'desire'.
(Other definitions for sir that I've seen before include "... ___ John Major" , "Polite term of address for a man" , "Male form of address" , "Polite form of address to a man" , "Noble title of undesirable kind" .)