strength vs vigour

strength and vigour both are nouns.

Word	Noun	Adjective	Verb	Adverb
strength	Yes	No	No	No
vigour	Yes	No	No	No

As nouns, vigour is a hyponym of strength; that is, vigour is a word with a more specific, narrower meaning than strength:

As nouns, vigour is a hyponym of strength; that is, vigour is a word with a more specific, narrower meaning than strength:

Other hyponyms of strength include brunt, impulse, momentum, energy, vigor, zip.

strength (noun)	vigour (noun)
the property of being physically or mentally strong	active strength of body or mind
an asset of special worth or utility	an imaginative lively style (especially style of writing)
permanence by virtue of the power to resist stress or force	forceful exertion
the amount of energy transmitted (as by acoustic or electromagnetic radiation)
capability in terms of personnel and materiel that affect the capacity to fight a war
physical energy or intensity
capacity to produce strong physiological or chemical effects
the power to induce the taking of a course of action or the embracing of a point of view by means of argument or entreaty
the condition of financial success