energy vs second wind

energy and second wind both are nouns.

Word	Noun	Adjective	Verb	Adverb
energy	Yes	No	No	No
second wind	Yes	No	No	No

As nouns, second wind is a hyponym of energy; that is, second wind is a word with a more specific, narrower meaning than energy:

Other hyponyms of energy include feistiness, scrappiness.

energy (noun)	second wind (noun)
forceful exertion	the return of relatively easy breathing after initial exhaustion during continuous exertion
an imaginative lively style (especially style of writing)	renewed energy or strength to continue an undertaking
enterprising or ambitious drive
(physics) a thermodynamic quantity equivalent to the capacity of a physical system to do work; the units of energy are joules or ergs
any source of usable power
a healthy capacity for vigorous activity