Where does “Egert” come from?

Egert (Estonian) comes from Hungarian -ért, from Hungarian ért, from Hungarian -t, from Proto-Uralic -tt.

Ancestry of “Egert”, step by step

Step	Language	Word	Meaning
1	Hungarian	-ért	for. Used to form the causal-final case
2	Hungarian	ért	to understand; to mean, construe; be familiar...
3	Hungarian	-t	Used to form the accusative case; -ed, -t. Used...
4	Proto-Uralic	-tt	—