| IRLY | | I really love you |
| irlydylm | | I really love you do you love me? |
| IRMC | | i rest my case |
| IRMFI | | I Reply Merely For Information |
| irmy | | I really miss you |
| irocc | | I rely on Christ completely |
| irof | | I roll on floor |
| iroflmfao | | I'm Rolling On Floor Laughing My Ass Off |
| iroi | | immediate return on investment |
| IROOC | | I've Run Out Of Cigarettes |
| IROOC | | Idiot Right Out Of College |
| irotf | | I'm rolling on the floor |
| IRR | | Internal Rate of Return |
| IRS | | Inland revenue service |
| irstbo | | it really sucks the big one |
| IRT | | in real time |
| IRT | | in regards to |
| IRT | | in reply to |
| irtf | | I'll return the favor |
| IRV | | immediate response vehicle |
| IRW | | in real world |
| irwtkyrn | | I really want to kiss you right now |
| ISAGN | | I See A Great Need |
| ISALY | | I Shall Always Love You |
| ISAPI | | Internet Server Application Program Interface |
| isb | | I'm so bored. |
| ISBAB | | I should have bought a book |
| ISBN | | International Standard Book Number |
| ISBT | | It's Strange But True |
| isbya | | im sorry but you asked |
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