gall

Noun (1)

Middle English galle, going back to Old English gealla, galla, going back to Germanic *gallōn-, galla- (whence Old High German & Old Saxon galla, Old Norse gall), going back to Indo-European *ǵholh₃-n- (whence, without the suffix, Greek cholḗ "bile, bitter hatred," chólos "bitter hatred, wrath," Avestan zāra- "bile"), a derivative of *ǵhelh₃- "green, yellow" — more at yellow entry 1

Note: The sense "boldness," first attested in the U.S. in the second half of the 19th century, is perhaps of independent origin.

Verb

Middle English gallen, in part derivative of galle gall entry 4, in part borrowed from Middle French galer "to scratch, rub, mount an attack on," derivative of gale "gallnut, callus," borrowed from Latin galla gall entry 3

Noun (2)

Middle English galle, borrowed from Anglo-French, borrowed from Latin galla "gallnut, oak apple," of obscure origin

Note: Latin galla cannot be akin to gall entry 4 if the latter does in fact descend from Indo-European *ǵholH-, and in any case the basic meaning of galla appears to be "excrescence" rather than "sore, blight."

Noun (3)

Middle English galle "sore on the skin, stain, evil, barren or wet spot in a field (in names)," probably in part going back to Anglian Old English *galla (West Saxon gealla) "sore on the skin of a horse," in part borrowed from Middle Low German galle "swelling in a joint, blastodisc, barren place," both nouns going back to Germanic *gallan- (whence also Old Norse galli "fault, flaw"), perhaps going back to an Indo-European base *ǵholH-, whence, from the derivative *ǵholH-r-, Norwegian galder "windgall," Old Irish galar "disease, pain," Welsh galar "mourning, grief"

Note: Perhaps additionally connected are Lithuanian žalà "harm, damage" (from *ǵholH-eh₂), Hittite kallar "nefarious thing, demon" (from *ǵholH-ro-), Old Church Slavic zŭlŭ "bad, evil" (from zero-grade *ǵhlH-o-). According to an older hypothesis the Germanic words are a borrowing from Latin galla "gallnut, oak apple" (see gall entry 3), but given the wide distribution and range of meanings of the Germanic words, this appears unlikely.