Definify.com

Webster 1913 Edition

Adj.

Full of spirit; possessing constitutional ardor; fiery;

as, a

mettlesome

horse

–

Met′tle-some-ly

adv.

–

Met′tle-some-ness

Noun.

Adj.

Full of spirit; possessing constitutional ardor; brisk; fiery; as a mettlesome horse.

mettlesome ‎(comparative more mettlesome, superlative most mettlesome)

of great mettle