Cisco no olho literally translates to "speck in the eye." It's an interesting and somewhat unique phrase that refers to a small particle or dust getting into one's eye, causing irritation and often tears.
In the context of the song, it's used as a common, almost cliché, excuse for crying. The lyrics mention "a desculpa do cisco no olho já tá manjada," meaning "the 'speck in the eye' excuse is already well-known/overused." This phrase highlights the singer's attempt to hide his true emotions (crying over a lost love) by blaming it on something trivial, but his excuse is no longer convincing.
Have you ever tried to act strong after a breakup, but secretly you're still a mess? That's the feeling at the heart of "Cisco No Olho." The title translates to "Something in My Eye," which is a classic excuse people use when they're trying to hide their tears. The singer tells a story of trying to move on by putting away photos and pretending not to care, so his ex won't have the "pleasure" of seeing him cry.
But all that pretending falls apart when he sees his ex again. He finally decides to be honest and admits, "I'm going to admit that I haven't forgotten you." He confesses that his life is a mess without her and that he's "dying of longing" (morrendo de saudade). It's a powerful song about dropping the tough act, admitting your mistakes, and being honest about how much you miss someone.