sex activity vs flood tide

sex activity and flood tide both are nouns.

Word	Noun	Adjective	Verb	Adverb
sex activity	Yes	No	No	No
flood tide	Yes	No	No	No

sex activity (noun)	flood tide (noun)
activities associated with sexual intercourse	the occurrence of incoming water (between a low tide and the following high tide)
	the highest point of anything conceived of as growing or developing or unfolding