...He is much of a gentlemen, and he has traveled enough to throw off that...
When or in which situation or condition would you rather use the bold part construction and could you please show me a synonym phrase or word for it?
Thanks in advance
In my opinion, much of is used when you want people to see the importance of the word following "much of". For example,
He is much of a traveler, than a shepherd.
The example above says that the subject is both a shepherd and a traveler. But he is more into travelling than in being a shepherd.
In AmE and I am pretty sure BrE, native speakers don't use much of in the sense you ask about: 'he is much of a gentleman'.
In English, the negative expression, as in 'he's not much of a gentlemen' is quite common.
She's not much of a lady.
He's not much of a singer/athlete/actor/writer/teacher/example/swinger/worker.
The meaning is given in Collns as
not to any appreciable degree or extent
and there are plenty of examples at that link.