The Collaborative International Dictionary
mammothrept
mammothrept \mam"mo*thrept\ (m[a^]m"m[-o]*thr[e^]pt), n. [Gr. mammo`qreptos; ma`mma grandmother + tre`pein to nourish.] A child brought up by its grandmother; a spoiled child. [R.]
O, you are a more mammothrept in judgment.
--B. Jonson.
Wiktionary
mammothrept
n. (context archaic English) A spoilt child.