comer:
(plural: ‘comers‘; pronunciation: the letter ‘c’ is said with a ‘k’ sound as in “king” — for the two different pronunciations of this word, please click here)

a newcomer (L)
a person who arrives at a place, in this context, ‘comer’ is usually combined with another word — ‘latecomer’, ‘newcomer’, etc.;
a person who appears to be very successful in his job, profession, business, politics, etc.,

a latecomer at the door
My niece is regarded a political comer., i.e. she is becoming more and more popular in politics and may become a leading politician soon.
All comers to the meeting are served cakes and coffee!
A teacher may allow or refuse to allow latecomers to her class, but does not have any choice in regard to the newcomers.
The expression ‘up-and-comer’ is used to refer to somebody who is new to a business, but he/she is making quick and promising progress.
