Answer: boning

AnswerCrossword Clue
BONINGBrushing (up)
BONINGDoing a butcher's chore
BONINGStudying hard
BONINGPreparing for an exam
BONINGCramming, with "up"
BONINGFish preparer's task
BONINGFilleting
boninga way of sighting along a row of poles
boningto remove the bones of
boningthe hard substance forming it
boningone of the structures composing the skeleton