lifeguard vs attender

lifeguard and attender both are nouns.

Word	Noun	Adjective	Verb	Adverb
lifeguard	Yes	No	No	No
attender	Yes	No	No	No

As nouns, attender is a hypernym of lifeguard; that is, attender is a word with a broader meaning than lifeguard:

lifeguard: an attendant employed at a beach or pool to protect swimmers from accidents
attender: someone who waits on or tends to or attends to the needs of another

Other hypernyms of lifeguard include attendant, tender.

lifeguard (noun)	attender (noun)
an attendant employed at a beach or pool to protect swimmers from accidents	someone who waits on or tends to or attends to the needs of another
	a person who is present and participates in a meeting
	someone who listens attentively