In medicine, IMAO stands for inhibitor of monoamine oxidase. It is a drug that is used as an antidepressant and its main application is in neurology and Psychiatry.In social networks, there is also this acronym which comes from the expression in English quot; in my arrogant opinion quot; meaning quot; in my arrogant opinion quot;. Arises in contrast of the old and worn out cliche in English IMHO = quot; in my humble opinion quot; meaning quot; IMHO quot;.