Bit of luck for a fatheaded fellow (5)
I believe the answer is:
fluke
'bit of luck' is the definition.
'fluke' can be an answer for 'luck' (fluke is a kind of luck). I'm not certain of the 'bit of' bit.
'a fatheaded fellow' is the wordplay.
I cannot quite understand how this works, but
'fellow' could be 'f' (abbreviation - of a society etc.) and 'f' is found within the answer.
The remaining letters 'luke' is a valid word which might be clued in a way I don't see.
This explanation may well be incorrect...
'for' acts as a link.
Can you help me to learn more?
(Other definitions for fluke that I've seen before include "flounder" , "One lucky" , "Chance happening" , "parasitic worm!" , "Parasitic flatworm" .)