Vurdumduymaz literally translates to "hit-feel-not", meaning someone who is indifferent or insensitive to what's happening around them, or to the feelings of others. It's a vivid and somewhat idiomatic word that isn't heard in every song.
In "Deli Kız," the singer uses this word to describe the object of his affection, highlighting her carefree and perhaps oblivious nature to his suffering. He sings, "Bu nasıl bir naz, vurdumduymaz" (What kind of coyness is this, so indifferent?), emphasizing her captivating yet seemingly unconcerned demeanor.
In "Deli Kız," which translates to "Crazy Girl," the singer describes a powerful and painful attraction to someone who is already taken. He uses musical metaphors to contrast their personalities: he is a sorrowful "old violin," while she is an unpredictable "crazy saz" (a Turkish stringed instrument) playing a tune he can't categorize as either traditional hicaz or modern jazz. This unique 'music' she plays sends a chill through his soul, yet at the same time, she is like "spring in my secluded garden," with a smile so beautiful it makes roses feel shy.
The chorus reveals the heart of his pain. He calls out to the "deli kız," admiring how beautiful she is but then sees her with her lover on her arm. This sight makes his heart ache and pound so hard he feels it will jump out of his chest. The repeated phrase "olmaz olmaz" ("it can't be, it can't be") captures his feeling of desperation and the impossible nature of his love for this captivating "crazy girl."