Translation of Spider-Slayer

What would the Sindarin translation of Spider-Bane, or Spider-Slayer be? I know that spider is Ungol, and bane/slayer is Dagnir. But I have no clue how it would go together. Any help will be greatly appreciated.

This does not yield good results at least to me anyways. Dagnirungol we be the best option as a compound. The other way is not good at all.

Dagnir Ungol would be “Slayer of a Spider” not as a compound.