coding vs decryption

coding and decryption both are nouns.

Word	Noun	Adjective	Verb	Adverb
coding	Yes	No	No	No
decryption	Yes	No	No	No

As nouns, decryption is a hyponym of coding; that is, decryption is a word with a more specific, narrower meaning than coding:

coding: act of writing in code or cipher
decryption: the activity of making clear or converting from code into plain text

Other hyponyms of coding include encoding, encryption, recoding, decipherment, decoding.

coding (noun)	decryption (noun)
act of writing in code or cipher	the activity of making clear or converting from code into plain text