Ele só precisa de uma caneta para lutar

What does “canetinha” mean in Portuguese?

Add -inha to caneta (“pen”) and you get canetinha — literally a “little pen,” but the suffix isn’t really about size. Portuguese diminutives also do attitude work: tacked onto something meant to be impressive, -inho/-inha can belittle it, marking it as weak, childish, or laughable. So canetinha boa (“nice little pen”) isn’t praise — it’s a sneer at a pen treated as a weapon.

Brazilian Portuguese leans on this dismissive diminutive constantly: a carrinho can be a toy car, a advogadozinho is a sneer at a small-time lawyer, and trabalhinho can wave off someone’s “little job.” The tone, not the suffix, decides whether it’s cute or cutting. Here the joke lands when a fighter, handed a pen as his random weapon, is mocked with “Canetinha boa” — the -inha shrinking the pen from “weapon” to “pathetic,” exactly the “weak or childish” pejorative use diminutives carry across many languages.