skin-dive vs skin diving

skin-dive and skin diving both are nouns.

Word	Noun	Adjective	Verb	Adverb
skin-dive	Yes	No	Yes	No
skin diving	Yes	No	No	No

As nouns, skin-dive and skin diving are synonyms defined as:

skin-dive and skin diving: underwater swimming without any more breathing equipment than a snorkel

skin-dive (noun)	skin diving (noun)
underwater swimming without any more breathing equipment than a snorkel	underwater swimming without any more breathing equipment than a snorkel

skin-dive (verb)	skin diving (verb)
swim underwater with no breathing apparatus other than a snorkel