sub-sincere

almost genuine, but not quite

"My sub-sincere appologies, I won't be able to interview with you at PPS"

sub par

below average. Deriving from the term in golf "par" meaning average, and sub meaning below.

the definitions below are sub par at best.

Sub Bot

Sub bot is used by the youtube channel T-Series.

T-Series jumped up by 9,000 subs instantly because of sub bot.

sub af

Someone who is submissive as fuck

Boy 1: "Bro Jessica will do anything I tell her to do"
Boy2: "She is sub af"

Scrub Sub

A substitute teacher who is gullible and half the time has no idea of what is going on around him/her.

--A class come into room and realizes they have a substitute teacher--

(Scrub Sub) "Do you have assigned seats?"
(Class) "No"
(That one annoying nerd that's always there) "Yes we do!"
(Scrub Sub) "I ain't no scrub sub!"

Sub-Bot

T-Series

Sub-bot is a very useful use.

sub-unit

A sub unit is a smaller group formed from the members of a larger kpop group for a music release or project, generally with a different concept from the original group.

"I really like 4minute's subunit 2Yoon"
EXO-CBX is the first offical sub-unit of EXO