whistling vs signaling

whistling and signaling both are nouns.

Word	Noun	Adjective	Verb	Adverb
whistling	Yes	No	No	No
signaling	Yes	No	No	No

As nouns, signaling is a hypernym of whistling; that is, signaling is a word with a broader meaning than whistling:

whistling: the act of signalling (e.g., summoning) by whistling or blowing a whistle
signaling: any nonverbal action or gesture that encodes a message

Other hypernyms of whistling include sign, signal, signalling.

whistling (noun)	signaling (noun)
the act of whistling a tune	any nonverbal action or gesture that encodes a message
the act of signalling (e.g., summoning) by whistling or blowing a whistle
the sound made by something moving rapidly or by steam coming out of a small aperture