Ultimate opening grabbed by English university man (8)
I believe the answer is:
eventual
'ultimate' is the definition.
(similar in meaning)
'opening grabbed by english university man' is the wordplay.
'opening' becomes 'vent' (vent is a kind of opening).
'grabbed by' indicates putting letters inside (inserted letters are grabbed inside).
'english' becomes 'E' (abbreviation as in OED).
'university' becomes 'U' (abbreviation for university).
'man' becomes 'Al' (man's name).
'e'+'u'='eu'
'vent' put into 'eu' is 'eventu'.
'eventu'+'al'='EVENTUAL'
(Other definitions for eventual that I've seen before include "Coming at last, ultimate" , "'Inevitable, with time (8)'" , "Final - happening as a consequence" , "Final, after a time" , "Occurring at the end, ultimate" .)