sit vs ride horseback

sit and ride horseback both are verbs.

Word	Noun	Adjective	Verb	Adverb
sit	No	No	Yes	No
ride horseback	No	No	Yes	No

As verbs, ride horseback is a hyponym of sit; that is, ride horseback is a word with a more specific, narrower meaning than sit:

sit: sit and travel on the back of animal, usually while controlling its motions
ride horseback: ride on horseback

Other hyponyms of sit include override, ride herd, outride, prance, canter, extend, gallop.

sit (verb)	ride horseback (verb)
serve in a specific professional capacity	ride on horseback
be in a position in which one's upper body is largely upright and supported by one's backside
show to a seat; assign a seat for
take a seat
be in session
sit and travel on the back of animal, usually while controlling its motions
assume a posture as for artistic purposes
work or act as a baby-sitter
be around, often idly or without specific purpose
be located or situated somewhere