勝かっ手て知しったる

expression, noun-modifying (irregular)

well aware of; know thoroughly; familiar with (and thus feel no need for restraint)

Used when someone knows a place, person, or situation so well that they act freely and without hesitation, often implying a sense of ease or lack of formality.

• 彼かれは勝かっ手て知しったる我わが家やのように振ふる舞まった。

  He acted as if he were in his own home, completely at ease.