Where does “dēnegāre” come from?

dēnegāre (Latin) comes from Latin negāre, from Proto-Indo-European né — not; no.

Ancestry of “dēnegāre”, step by step

Step	Language	Word	Meaning
1	Latin	negāre	—
2	Proto-Indo-European	né	not; no

dēnegāre — Etymology, Origin & Word History | Etymology Explorer