I offer nothing after initially losing desire (6)
I believe the answer is:
libido
'desire' is the definition.
(I know this)
'i offer nothing after initially losing' is the wordplay.
'offer' becomes 'bid' (bid is a kind of offer).
'nothing' becomes 'O' (looks like zero - 0).
'after' is a charade indicator (letters next to each other).
'initially' says to take the initial letters.
The first letter of 'losing' is 'l'.
'i'+'bid'+'o'='ibido'
'ibido' put after 'l' is 'LIBIDO'.
(Other definitions for libido that I've seen before include "lust!" , "Strong urge" , "Instinctive desire" , "Psychic, sexual, energy" , "Emotional energy associated with sexual desire" .)