Gǽlsa

According to the Old English Dictionary:

an;

gǽlsa

m. A glutton; fig. one who is inordinately fond of a pursuit:--Gif mann bið ákenned on xxvi nihta ealdne mónan, sé bið weorces gǽlsa (he will be a glutton of work), Lch. iii. 158, 15. [Cf. O. H. Ger. geilisón luxuriare.] gælsa