This is the 13574th most frequent Polish word.
pistoletu
The Polish word "pistoletu" means "of the pistol" (genitive singular form).
Here, 'pistoletu' is the genitive singular form of 'pistolet' used after the verb 'dotykać' which requires the noun to be in genitive case.
Nie dotykaj tego pistoletu, jest niebezpieczny.
Don't touch that gun, it's dangerous.
Here, 'pistoletu' is again in the genitive singular form since the verb 'szukać' governs the genitive case.
On szuka pistoletu, który zgubił.
He is looking for the gun that he lost.
Similarly, 'pistoletu' appears in the genitive singular to match the negation structure with 'nie ma', which mandates the noun to be in genitive case.