Competitive Speak

I personally didn't find them to be confusing, with the exception of BP, which can either mean Baton Pass or Bullet Punch (and in some cases, [member='Bionic Puppy']) Other are fairly easy to guess, such as GyaraVire, and EdgeQuake.

 

Hax. Need I say much more?

 

SubSeed (Substitute + Leech Seed)
DDance (Dragon Dance)
Rocks (Stealth Rock)
Para Hax (Paralysis' Effect being too strong)
SE (Super Effective)
HP (Hidden Power) or (Health Points)

There are so many more but I guess it depends on the battle itself with what abbreviations are used.

 

I love using LO (Life Orb, which often gets confused with Leftovers).

 

I like a lot of the name abbreviations like pdon (Primal Groudon) and pogre (Primal Kyogre).

Also, there's stuff like CroCune (max HP/def , cm, scald, rest talk suicune) and Brazilian Tar (Max Sp def, Rocks, T-wave, ice beam/fire blast, pursuit tyranitar) which have nothing to do with the sets themselves but more to do with the users that made them popular.

But I get what you're saying when it comes to jargon, just like anything else, it can get confusing but is really convenient at the same time.

Saying something like:

"I'm running an HO team with balloon dual dance Cobalion, NG t-flame, and stallbreaker garde" (which is on one of my teams lol)

is a lot easier than saying:

"I have a hyper offense team that has a rock polish and Swords Dance Coballion on a air ballon, a Talonflame that has natural gift, and a Max speed, high special attack Mega Gardevoire w hyper voice/psyshock that's meant to destroy mons that are slow and have high defences/special defences."