Desilusionado means "disillusioned" or "disappointed." It's a strong emotional word that goes beyond simple sadness, implying a loss of hope or belief in something.
In the song, Yahir uses it to describe his state before meeting his love, singing, "Me había dado por vencido, desilusionado y confundido." This word powerfully conveys the depth of his prior despair, making the arrival of love even more impactful.
Have you ever felt like giving up on love? Like you've been disappointed and confused so many times that you just think, "this is how it's going to be"? That's exactly where Yahir was before he met the person this song is about.
He sings about how he'd given up on his dreams and finding someone to truly love him, feeling like he was stuck. But then, boom! This person arrived in his life and changed everything! They "acomodaste lo que sobraba" [tidied up what was left over] and "sacaste el polvo que me estorbaba" [removed the dust that was bothering me]. They gave him passion and hope back, making him believe in love again. It's such a sweet song about finding unexpected love that completely turns your world around!