boyish

adj

1. Like a stereotypical boy in appearance or demeanor.

   “People disliked his boyish and juvenile behaviour.”

   “Her boyish figure belied her femininity.”

   “He did so, but very soon stopt again to say, “the piano-forte! Ah! That was the act of a very, very young man, one too young to consider whether the inconvenience of it might not very much exceed the pleasure. A boyish scheme, indeed!—I cannot comprehend a man’s wishing to give a woman any proof of affection which he knows she would rather dispense with; and he did know that she would have prevented the instrument’s coming if she could.””

   “He is never expected to act like a nice little gentleman, for he is only a rude little slave. Thus, freed from all restraint, the slave-boy can be, in his life and conduct, a genuine boy, doing whatever his boyish nature suggests; […]”

   “There were no signs and no one quite knew how to navigate the museum, including, as it was Fleet Week, gaggles of boyish sailors all in their summer whites. It looked like a Frank Sinatra movie.”

2. Relating to a boy, or occurring in boyhood.

   “For Memnon […] fought hand to hand with his overmatch, and met his boyish and most dolorous death beneath the walls of Troy.”