Nephewish

In the good old days no family was complete without a spinster aunt to turn to in seasons of distress and grief, measles, whooping-cough, visiting, absence of parents, or unexpected company. More than any other woman, possibly, the spinster aunt has become New.[…]As a type of auntliness she is no longer plentiful, ubiquitous and tenderly considerate of a niecely sneeze or a nephewish whimper, of a brother-in-law’s slippers or a sister-in-law’s gruel or tea.

Source: wiktionary

“[…]You’re sure the hell not my nephew, and—” she waggled her finger at me “—if I ever catch a nephewish look in your eye or a nephewish tone in your voice, you can start ducking your head, ’cause the nearest brick has already started toward you.”

Source: wiktionary

‘Now you’re being nephewish. I think I prefer you as a quiffy gallant.’

Source: wiktionary