Boussa is a French slang word for "kiss", derived from Arabic. It's a charming and less common alternative to the standard French word for kiss, "baiser" or "bisou".
In the song, the artist sings, "Ton affection me manque, tes caresses, tes boussa" (I miss your affection, your caresses, your kisses). This word adds a touch of intimacy and cultural flavor, making it stand out and feel more personal within the lyrics.
Josas's