Lackey's hint for Spooner: 'I'm going' (6-3)
I believe the answer is:
toodle-pip
'i'm going' is the definition.
(toodle-pip may be said when saying goodbye)
'lackey's hint for spooner' is the wordplay.
I cannot quite understand how this works, but
'for' could be 'to' (eg both can mean 'in the opinion of') and 'to' is located in the answer.
This may be the basis of clue (or it may be nonsense).
(Other definitions for toodle-pip that I've seen before include "Farewell remark - dipole top (anag)" , "Farewell (informal)" , "Goodbye (dated)" , "so long" , "Take care" .)