spying vs espial

spying and espial both are nouns.

Word	Noun	Adjective	Verb	Adverb
spying	Yes	No	No	No
espial	Yes	No	No	No

As nouns, spying and espial are synonyms defined as:

spying and espial: the act of detecting something; catching sight of something

Other synonyms of spying include catching, detection, spotting.

spying (noun)	espial (noun)
the act of keeping a secret watch for intelligence purposes	the act of detecting something; catching sight of something
keeping a secret or furtive watch
the act of detecting something; catching sight of something