This is the 5046th most frequent Turkish word.
gözüken
"Appearing" or "seeming."
In this context, 'gözüken' modifies 'problem' to denote 'the problem that appears or is apparent'.
Gözüken problem çok basit çözülebilir.
The apparent problem can be solved very simply.
In this sentence, 'gözüken' is used as an adjective derived from the verb 'gözükmek' (to appear). It describes 'kişi' (person) as 'the person that appeared'.
Gözüken kişi kimdi?
Who was the person that appeared?
Here, 'gözüken' serves as an adjective qualifying 'işaret' (sign), implying the sign that is visible.