시큼한 is a descriptive adjective that means 'sour' or 'tangy', often used for food and drinks, but rarely applied to a person in your typical love song.
In the lyrics, ATEEZ sings "시큼한 type, 자극" (sour type, a thrill), playing off the 'lemon drop' theme to describe a love interest whose personality is sharp, exciting, and irresistibly stimulating. It's a fresh and sensory way to capture the electric, complex pull of attraction, like tasting something sharply sweet and sour at the same time.
ATEEZ's 'Lemon Drop' is such a fun, high-energy track about being completely captivated by someone who's just irresistible! From the very start, the lyrics tell us, "Ain't nobody, yeah 너만 보여 여기에 [Only you are visible here]" and "Yeah, 자꾸만 너에게 끌려, too insidious [I keep getting drawn to you, too insidious]." It's like this person is a total muse, inspiring them so much that it feels like an "Emergency, emergency, you put me in an emergency." They're so drawn in, even though they admit, "사랑은 완벽하진 않지만 [Love isn't perfect, but]" this person is both "쓰고 달고 그래 한 상에 차려진 [bitter and sweet, served on one table]." They're even a little bit dangerous, saying, "넌 너무 나빠 [You're too bad]" and "더는 자극하지 마 [Don't provoke me anymore]" – but in a good way!
The song really sets a scene for a hot summer night, with lyrics like "뜨거워 여름밤 열기 [Hot summer night heat]" and the idea of it being just "너와 나 둘만의 [just you and me]." It's all about that intense, almost crazy heat they feel. The chorus invites us to raise a glass with "Lemon drop, lemon drop, closer 조금 더 [a little more]" and "Tequila, tequila sunrise," wanting to "Stay up all night 'til sunrise." It perfectly captures that feeling of wanting to spend every moment with someone who's exciting, a little bit sour, a little bit sweet, and completely unforgettable.