fail vs betray

fail and betray both are verbs.

Word	Noun	Adjective	Verb	Adverb
fail	No	No	Yes	No
betray	No	No	Yes	No

As verbs, fail and betray are synonyms defined as:

fail (verb)	betray (verb)
stop operating or functioning	give away information about somebody
deteriorate	reveal unintentionally
prove insufficient	cause someone to believe an untruth
disappoint, prove undependable to; abandon, forsake	disappoint, prove undependable to; abandon, forsake
become bankrupt or insolvent; fail financially and close	deliver to an enemy by treachery
be unsuccessful	be sexually unfaithful to one's partner in marriage
fail to get a passing grade
fail to do something; leave something undone
judge unacceptable
be unable
fall short in what is expected