First man in this time this morning (4)
I believe the answer is:
adam
'first man' is the definition.
(first man in the Bible)
'this time this morning' is the wordplay.
'this time' becomes 'AD' (AD, Anno Domini, as opposed to BC, Before Christ).
'this morning' becomes 'am'.
'ad'+'am'='ADAM'
'in' acts as a link.
(Other definitions for adam that I've seen before include "Male" , "who transformed Palladian architecture?" , "Robert -, Sc. architect" , "Eden inhabitant" , "- - Bede by George Eliot" .)