megrims noun[plural only]2 •Chiefly preceded by the: depression, low spirits, unhappiness.Thou art properly my cephalick snuff, and art no bad medicine against megrims, vertigoes, and profound thinking—ha, ha, ha. — 1766 •Any of various diseases of animals, especially horses, marked by a disturbance of equilibrium and abnormal gait and behaviour such as staggers or a sudden vertigo, sometimes followed by unconsciousness; the staggers.