Abare comes from the word abareru which means Violent/violence/force/rage/to act violently. In 2D fighters it is regarding a character's ability to deal damage of random hits and trades, trying to land pokes between an opponent's attacks. Usually done when a player is under pressure.

Unblockables come in two forms, either they are moves that can bypass your guard/block and hit you. This type if move must be avoided in order to not recieve damage. The second type of unblockable refers to attacks which hit your opponent in such a way that it is extremely/impossible for them to defend against. This can either be in the form of hit [..]

An MVC term. Basically means a combo pulled off in the air with both characters being airborne.

A move performed in the air against your opponent's aerial move

Autoguard Frames are, in a nutshell, Frames where you will autoguard moves aimed at you. the body parts it autoguards and the autoguard duration vary, but they normally dont last the entire Move. Autoguard frames are normally inferior to invincible Frames because you still have a hitbox and thus can Grabbed out of the Autoguard, or get hit enough t [..]

Baiting means to perform a move (that is usually safe) and trying to get some sort of reaction out of your opponent whereby you may be able to punish that move with a combo, distortion, astral, etc.

In the context of a fighting game balance refers to the whether the character is stronger or weaker than others. A good balance generally refers to most of the characters being on an equal level/playing field with other characters in terms of health, power, etc.

Block stun refers to when you block an attack and are unable to move for a short period. The only way for you to get out of block stun is by bursting (in blazblue) or using x-factor (in marvel vs capcom)

A block string is when a player is forced into a constant state of blocking due to an opponent's constant barrage of attacks. This is useful for pushing your opponent into certain positions/situations where they either cannot attack or they are pressured into doing something that leaves them wide open to attack.

A BnB is a set of combos that are the most basic Combos used for a character.