Wikipedia
IANAL is a Usenet and chat abbreviation ( initialism) for "I am not a lawyer". It may be used by non-lawyers seeking to avoid accusations of unauthorized practice of law or lawyers clarifying that they do not have enough information to provide advice, and are not making any recommendation to the particular addressee of their remarks.
A related abbreviation, TINLA, stands for "This is not legal advice." One or both of these abbreviations usually precede opinions about law. The use of these abbreviations serves as a warning for the reader not to take the opinion as professional legal advice. Many jurisdictions have legal restrictions on actually giving or even appearing to give legal advice, or otherwise practicing as a lawyer without legal qualifications and official registration. Rendition of legal advice by a person who is not licensed to do so can be the basis for a charge of unauthorized practice of law.