estrus vs physical condition

estrus and physical condition both are nouns.

Word	Noun	Adjective	Verb	Adverb
estrus	Yes	No	No	No
physical condition	Yes	No	No	No

As nouns, physical condition is a hypernym of estrus; that is, physical condition is a word with a broader meaning than estrus:

estrus: applies to nonhuman mammals: a state or period of heightened sexual arousal and activity
physical condition: the condition or state of the body or bodily functions

Other hypernyms of estrus include physiological condition, physiological state.

estrus (noun)	physical condition (noun)
applies to nonhuman mammals: a state or period of heightened sexual arousal and activity	the condition or state of the body or bodily functions