(dated) Behaviour befitting, or typical of, a young lady.
1860, Grace Wharton, Philip Wharton, The Queens of SocietyThough Lady Mary had none of the young-ladyism or sentimentality of girls of her age, we are not to suppose her either hard or masculine.
1869, Louisa May Alcott, An Old-Fashioned GirlBut her attention was speedily diverted by the squabble going on in the corner; for Fanny, forgetful of her young ladyism and her sixteen years, had boxed Tom's ears ...
