These will only be ToP-related abbreviations and acronyms that I've seen used; dictionaries for 1337 and mmorpg-speak can be found practically everywhere on the internet.Oh well, some of the most common ones are in here. No further explanations of the words will be given though.

Some things can have more than one meaning, please let me know if you notice anything along that line.

Hope this can help somewhat - I know I could have used it when I was a poor noob

Abaddon----> Actually the name of an area, entrance from treasure bay
aggro----> 1: aggressive monsters. 2: to draw attention of aggressive monsters
AM----> Abyss Mire, skill
AoE----> 1: Armor of Eva./Armor of Engima (Evanescence and Enigma gets mixed up a lot I've noticed)
AoE----> 2: Area of effect
aspd----> attack speed
BDL----> Black Dragon Lair
BoE----> 1: Blades of Enigma
BoE----> 2: Bellow of Evanescence. (Weapon for lvl 55 Sharpshooter)
BAoE----> Battle Armor of Enigma

B(A)oE----> Battle Armor of Eva
BC----> 1: Battle cleric (offensive cleric build)
BC----> 2: Beautiful chest
BD----> Black Dragon
BM----> Black market
BoI----> Blade of Incantation
bolt----> 1: Lightning Bolt, skill
bolt----> 2: Spiritual Bolt, skill
BoS----> Battlearmor of Sistine
buff----> 1. Additional defense using support skills
                2. to give someone the noun explained in (1)
CA----> 1: Chaos Argent

CA----> 2: Catacomb armor (yes, I've seen this used)
CA frame----> Chaos Argent framestone
CB----> Charmed berry
CF----> Cursed Fire, skill
champ----> Champion
claw----> clawstone
cler----> Cleric
colo----> Gem of Colossus
convoy----> Voyager with high con
crus/cruz----> Crusader

DB----> Deep Blue
DoE----> Dance of Evanescence
Drakan----> Not an abbreviation. Name of equipment.
DS----> Dark Swamp, maze for levels 45-55
DSM----> Dual sword mastery
DW----> Demonic World, maze for levels 55+
EBD----> Eye of Black Dragon
enf----> Enfeeble, skill
Eni----> Enigma
eq----> equipment (armor,weapons,gloves etc)

ES----> Energy Shield, skill
Eva----> Evanescence
eva (chest)----> Evanescence chest of....
FC----> Forsaken city, maze for levels 35-45
frame----> framestone
FS----> Full support (build of cleric or sm, used to mostly support parties)
f/w----> fused with
GAM----> Great Argent Mango (or Gr8 AM)
GM----> Game Master. Sort of an in-game police.
GoC----> Gem of Colossus
GoR----> Gem of Rage
GoS----> Gem of Soul

GoW----> Gem of Wind
GSB----> Great Shaitan Biscuit (also GR8 SB)
GSDF----> Great Snow Dragon Fruit (GR8 SDF)
GWS----> Great White Shark, ship type
HB----> Heaven's berry
herb----> Herbalist
hex----> Hexathlon
(hi)-amp----> (Hi)-Amplifier of Strive
hp----> health points
idk----> I dont know

IM----> Item mall
IMP----> Item mall points
inca (chest)----> Incantation chest of...
IS----> Illusion slash, skill
JoE----> Judgement of Enigma (Unsealed level 65 weapon for champion)
KS----> Kill steal
LT----> Lone Tower
lust----> Lustrious gem
lvl----> level (yeah, I guess you figured this one out)
MC----> Mystic chest
MO----> Magical Ocean
MSW----> Mini-Sacred War

nado----> Tornado, skill
nana----> Party EXP fruit (short for banana, actually)
newbie/newb----> beginner, not familiar with the game
noob----> A not-so-nice way of calling someone a newbie. A noob will probably call you a noob.
NSS----> New Sheepskin Scroll
Oath----> Stone of Oath
OSS----> Old Sheepskin Scroll. Can be obtained from Story quest or fortune lots.
paw----> pawstone
PCS----> Platemail of the Cursed Soul
pr----> physical resist
rats----> Fairy rations

ref (gem)----> refining gem
RoD----> Robe of Death (Hunter armor)
sader----> Crusader
SB----> 1: Shaitan biscuit
SB----> 2: Spiritual bolt, skill
SBT----> Seabed Tunnel
SD----> Soul Detector
Sea Voy----> Build of Voyager that focuses on sea skills instead of land
SI----> Shadow insignia, skill
skel----> skeletar

slash----> Illusion Slash, skill
Slasher----> Build of crusader that focuses on getting the maximum damage for their Illusion Slash
SM----> Seal Master
SoE----> Seal of Elder, skill
solo----> Killing and/or tresure hunting without the help of others
sp, noun----> spirit points
sp, verb----> break (sitting in safe area) to regain sp points
SS----> 1: Sharpshooter
SS----> 2: Shadow Slash, skill
SW----> Sacred War
swordie----> Swordsman

tank, noun----> Usually referring to Champions, and usually meaning full-con
tank, verb----> to be able to aggro/take hits (all classes)
Tix----> Tickets
ToD----> Touch of Death (Hunter weapon)
tp, tele----> teleport (no, not the paper-kind-tp...! Shame on you!   )
TS----> True Sight, skill
UG----> Unique gem
Uns----> Unsealed
UT----> Underwater Tunnel
voy----> Voyager
Wyrm----> Not an abbreviation. Name of equipment.

ZFF----> Zephyr Fish Floss