The clue is,
"Hear hard men are thrown out of short meeting (5)"
Answer "Tryst".
"Hear" means "try", as a judge does at court.
"h" is an abbreviation of "hard".
"Men" in the Armed Forces are "Other Ranks", or "OR".
Throw out "h or" from "short" and you are left with "st".
Add "st" to "try" and you have "tryst" for a meeting.