Often used in a slightly derogatory or familiar way for a young boy or inexperienced person. Can be affectionate or dismissive depending on context.
That brat is always up to mischief.
He's just a kid, but he's so cheeky.
young Buddhist monk; novice monk
Specifically refers to a boy or young man training at a Buddhist temple. Not a general term for a young person.
The young monk at the temple was cleaning from early morning.
shop boy; errand boy; apprentice
Historical or traditional term for a young male apprentice or servant in a shop or business. Rare in modern contexts except in period settings.
In the Edo period, shop boys ran errands for merchant houses.
That kid acts so full of himself even though he's still just a brat.
You little brat, you've been up to no good again!
In his youth he worked as an errand boy at a liquor shop.
one-eyed goblin; one-eyed monster
snot-nosed kid; brat