Oceanside groomer

I was maybe in my teens when I suddenly realized that suitcase actually came from suit and case. It struck me as outrageously funny that I hadn't realized something so obvious before! ;-)

For each of the following compound words substitute synonyms for its component words. You can shoot for the same meaning or be more freeform and see what happens. You may come up with a word that means the opposite. :-)

So, if the word were beachcomber you might change it to shoresearcher or shorebrusher or oceansidegroomer or coastdetangler.

aircraft
ballroom
cowboy
dimwit
earthquake
frostbite
globetrotter
highway
ironclad
jellyfish
knothole
lawsuit
mastermind
nightfall
outlaw
pancake
quicksilver
raincoat
scarecrow
tattletale
underwear
vainglory
wallflower
xylophone <-- fudging a bit for x, though it's a compound in Greek!
yearbook
zookeeper