gemæstan

By surface analysis, ġe- +‎ mæstan.

• IPA^(key): /jeˈmæs.tɑn/

ġemæstan

1. (transitive) to fatten
   • Homilies of the Anglo-Saxon Church

     Him becōmon ēac swā miċele welan tō handa, þæt his bīġleofa wæs ælċe dæġ mid his hīrede þrittiġ mittan clǣnes melowes, and sixtiġ mittan ōðres melowes, twelf fætte oxan, and twēntiġ feldoxan, hundtēontiġ weðera, buton huntoðe and fugoloðe and ġemæstra fugela.

     And so much wealth came into his hands that every day he and his household consumed thirty mittas of clean meal, sixty mittas of other meal, twelve fat oxen, twenty field-oxen, and one hundred wethers, not counting the sustenance from hunting, fowling, or fattened birds.

• Joseph Bosworth, T. Northcote Toller (1898) “ge-mæstan”, in An Anglo-Saxon Dictionary, second edition, Oxford: Oxford University Press.