IINM
Origin
Abbreviation of if I'm not mistaken.
Full definition of IINM
Adverb
IINM
- (Internet slang) if I'm not mistaken.
Usage notes
This is used to qualify a statement of fact, toning down how strongly it is being asserted. In short, the speaker (or, more typically, typist) is stating that he may be wrong about the fact.