Very strong man in Cheers , playing university lecturer (8)
I believe the answer is:
hercules
'very strong man' is the definition.
(mythological strong man)
'in cheers playing university lecturer' is the wordplay.
'in' means one lot of letters goes inside another.
'playing' indicates anagramming the letters.
'university' becomes 'u' (abbreviation for university).
'lecturer' becomes 'l' (abbreviation for lecturer).
'cheers' with letters rearranged gives 'herces'.
'u'+'l'='ul'
'herces' enclosing 'ul' is 'HERCULES'.
(Other definitions for hercules that I've seen before include "Mighty hero of Greek mythology" , "A very powerful man" , "Strong man of mythology" , "Strong hero" , "Greek hero who carried out 12 labours" .)