Where does “épier” come from?

épier (French) comes from Middle French espier, from Old French espier, from Vulgar Latin spiare, from Frankish spehōn, from Proto-Germanic spehōną, from Proto-Indo-European speḱ- — to see, to look, to observe.

épier (French): to spy on, keep an eye on, watch; to watch for;...

Definitions

to spy on, keep an eye on, watch; to watch for;...

Ancestry of “épier”, step by step

épier traces back through two separate lines of ancestry.

via Middle French espier

Step	Language	Word	Meaning
1	Middle French	espier	to watch
2	Old French	espier	to watch
3	Vulgar Latin	spiare	present active infinitive of *spiō
4	Frankish	spehōn	to spy, watch; to peer, to look, to spy
5	Proto-Germanic	spehōną	to peer, look, spy
6	Proto-Indo-European	speḱ-	to see, to look, to observe

via Latin spicare

Step	Language	Word	Meaning
1	Latin	spicare	to furnish with spikes, or ears

Every word from Proto-Indo-European speḱ- →Every word from Proto-Germanic spehōną →Every word from Frankish spehōn →