[1] After several years in the West Indies, he visited America where he made the acquaintance of Benjamin Franklin, before returning to Britain and settling in Andover, in Hampshire.
[3] Following the outbreak of American Revolutionary War, he returned to Antigua where he was appointed physician to Monk's Hill, and as one of the assistant judges of the Courts of King's Bench and Common Pleas.
These arose partly from a determined opposition to quackery, but was also attributed to his hot temper, as evidenced by his time served in Winchester Gaol for issuing a challenge to a duel.
[2] He was most famously involved in a long running dispute with Phillip Thicknesse, which began after the latter took exception to a presumed insult in Medical Cautions.
After a number of back and forths, including a dedication in which Adair referred to his rival as “Censor-General of Great-Britain, Professor of Empiricism, and Nostrum, Rape, and Murder-Monger to the St. James's Chronicle“, Adair published a book containing so-called errata to Thicknesse's memoirs, presumably fabricated, accompanied by a satirical woodcut frontispiece.