Cowgirl is a hyponym of cowpoke.
Cowpoke is a hypernym of cowgirl.
As nouns the difference between cowpoke and cowgirl
is that
cowpoke is (us|slang) a cowhand (one who tends free-range cattle) while
cowgirl is a woman who tends free-range cattle, especially in the american west.
As a verb cowgirl is
(rare|intransitive) to work as a cowgirl, herding cattle.