Poirot's a strong man (8)
I believe the answer is:
hercules
'man' is the definition.
(I have seen 'Strong man' mean 'hercules' so perhaps 'man' could also mean 'hercules')
'poirot's a strong' is the wordplay.
'poirot' becomes 'hercule' (Hercule Poirot).
'a strong' becomes 's' (this could be a standard abbreviation I've not previously seen).
'hercule'+'s'='HERCULES'
Can you help me to learn more?
(Other definitions for hercules that I've seen before include "A very powerful man" , "Mighty hero of Greek mythology" , "Hero of Greek myth who performed 12 great labours" , "Twelve-labours myth. hero" , "Mythical strongman - he's cruel (anag)" .)