Look up this word
mystery

In a sentence
Prečo spáchal samovraždu je stále záhadou.
Why he killed himself is still a mystery.
Toto je záhada.
This is a mystery.
Practice frame
Examples from Tatoeba (CC BY 2.0 FR).
Source
Slovak National Corpus (SNK) ↗English gloss from the frequency publish path. Includes Tatoeba example sentences when present.
Full attribution on References.