signal vs foretell

signal is a noun but foretell is not a noun.

Word	Noun	Adjective	Verb	Adverb
signal	Yes	Yes	Yes	No
foretell	No	No	Yes	No

As verbs, foretell is a hyponym of signal; that is, foretell is a word with a more specific, narrower meaning than signal:

signal (noun)	foretell (noun)
any nonverbal action or gesture that encodes a message
any incitement to action
an electric quantity (voltage or current or field strength) whose modulation represents coded information about the source from which it comes

signal (adjective)	foretell (adjective)
notably out of the ordinary

signal (verb)	foretell (verb)
communicate silently and non-verbally by signals or signs	make a prediction about; tell in advance
be a signal for or a symptom of	indicate, as with a sign or an omen
	foreshadow or presage