precautional vs precautionary

precautional and precautionary both are adjectives.

Word	Noun	Adjective	Verb	Adverb
precautional	No	Yes	No	No
precautionary	No	Yes	No	No

As adjectives, precautional and precautionary are synonyms defined as:

precautional and precautionary: taken in advance to protect against possible danger or failure

precautional (adjective)	precautionary (adjective)
taken in advance to protect against possible danger or failure	taken in advance to protect against possible danger or failure