Unsisterly

[…] I desire I may throw myself at my father’s and mother’s feet, and hear from them what their sentence is. I shall at least avoid, by that means, the unsisterly insults I meet with from you.

Mary was not so repulsive and unsisterly as Elizabeth, nor so inaccessible to all influence of hers […]

Felicity tossed her golden head and shot an unsisterly glance at Dan.