detection vs espial

detection and espial both are nouns.

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

As nouns, detection and espial are synonyms defined as:

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

Other synonyms of detection include catching, spotting, spying.

detection (noun)	espial (noun)
the act of detecting something; catching sight of something	the act of detecting something; catching sight of something
a police investigation to determine the perpetrator
the perception that something has occurred or some state exists
the detection that a signal is being received