可能來自pet,寵愛，寵兒，-ish,形容詞后綴。引申詞義得寵的，任性的，使性子的。
It has naturally been assoc. with PET sb.1, as being a characteristic habit of a "pet" or indulged and spoiled child; but the connexion of sense is not very clear or simple .... [OED]Related: Pettishly; pettishness.
來自辭典例句