Where does “praty” come from?

praty (Middle English) comes from Old English prættiġ, from Proto-Germanic prattugaz, from Proto-Germanic -gaz, from Proto-Indo-European -ḱos — -y, -ic.

Ancestry of “praty”, step by step

Step	Language	Word	Meaning
1	Old English	prættiġ	tricky, crafty, sly, cunning, wily, astute
2	Proto-Germanic	prattugaz	boastful, sly, slick, deceitful, tricky, cunning
3	Proto-Germanic	-gaz	-y
4	Proto-Indo-European	-ḱos	-y, -ic

Every word from Proto-Indo-European -ḱos →Every word from Proto-Germanic -gaz →Every word from Proto-Germanic prattugaz →