hobby

Etymology 1

Shortened from hobby-horse, from Middle English hoby, hobyn, hobin (“small horse, pony”), from Old French hobi, *haubi, haubby, hobin ("a nag, hobby"; > Modern French aubin, Italian ubino), of Germanic origin: from Old French hober, ober (“to stir, move”), from Old Dutch hobben (“to toss, move up and down”); or from North Germanic origin related to Danish hoppe (“a mare”), Old Swedish hoppa (“a young mare”), North Frisian hoppe (“horse”); both ultimately from Proto-Germanic *huppōną (“to hop”), from Proto-Indo-European *kewb- (“to bend; a bend, joint”). More at hop, hobble. The meaning of hobby-horse shifted from "small horse, pony" to "child's toy riding horse" to "favorite pastime or avocation" with the connecting notion being "activity that doesn't go anywhere". Possibly originally from a proper name for a horse, a diminutive of Robert or Robin (compare dobbin).

noun

1. An activity that one enjoys doing in one's spare time.
   I like to collect stamps from different countries as a hobby.
   take up a hobby
   give up your hobby
2. (equestrianism) An extinct breed of horse native to the British Isles, also known as the Irish Hobby

Etymology 2

From Middle English hoby, hobeye, from Old French hobé, hobei, hobet, from Medieval Latin hopētus, diminutive of harpe.

noun

1. Any of four species of small falcons in the genus Falco, especially Falco subbuteo.
   He hawked – from nearby Esher, Richard Fox sent a servant with a hobby, which Henry received enthusiastically – and hunted, sending a present of freshly slaughtered deer to Princess Mary. 2011, Thomas Penn, Winter King, Penguin, published 2012, page 323