Arrequerelam is a less common, somewhat informal verb that means "they show off" or "they flaunt". It implies a superficial display, often of wealth or status, without necessarily having the substance to back it up.
In the song, the artist uses it to contrast those who merely show off with those who truly understand the struggles of life, singing, "Arrequerelam, mas não sabem nada / Do que é andar de cintura pesada" (They show off, but they know nothing / Of what it's like to walk with a heavy waist). This word adds a unique flavor to the lyrics, highlighting the theme of authenticity versus pretense.
Nininho Vaz Maia's "AVELINO" is a really direct and powerful song. He's basically calling out someone named Avelino, asking him, "Avelino, diz-me quanto é que apostas / Que caminhando com este mundo nas costas / Não ias ter a resposta como encontrei pra ti" [Avelino, tell me how much you bet / That walking with this world on your shoulders / You wouldn't have the answer like I found for you]. It sounds like Avelino is struggling, and Nininho is telling him he needs to show himself some love and care for what he likes, because his current way of living isn't working for him.
The song really hits hard when Nininho talks about people who "Arrequerelam, mas não sabem nada" [Complain, but know nothing] about what it's like to carry a heavy burden, to see night turn into dawn, and to live with fear. He repeats, "Ninguém fez nada por mim" [No one did anything for me], emphasizing a feeling of having faced tough times alone. It's a blunt reminder that some people talk a lot, but they don't understand the real struggles others go through.