spying vs detection

spying and detection both are nouns.

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

As nouns, spying and detection are synonyms defined as:

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

Other synonyms of spying include catching, espial, spotting.

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