warn vs tell

warn and tell both are verbs.

Word	Noun	Adjective	Verb	Adverb
warn	No	No	Yes	No
tell	No	No	Yes	No

As verbs, tell is a hypernym of warn; that is, tell is a word with a broader meaning than warn:

warn: ask to go away
tell: give instructions to or direct somebody to do something with authority

Other hypernyms of warn include enjoin, order, say.

warn (verb)	tell (verb)
notify of danger, potential harm, or risk	discern or comprehend
advise or counsel in terms of someone's behavior	mark as different
notify, usually in advance	let something be known
ask to go away	narrate or give a detailed account of
	give instructions to or direct somebody to do something with authority
	give evidence
	express in words
	inform positively and with certainty and confidence