weasel, skunk, ermine
鼬 centers on small, slender carnivorous mammals known for their musky odor: weasels, skunks, and ermines. The meanings are closely related animals within the same broad family.
weasel (esp. the Japanese weasel, Mustela itatsi)
Japanese weasel (Mustela itatsi)
Korean yellow weasel (Mustela sibirica coreana)
polecat (Mustela putorius); ferret; fitch
mongoose
cut in the skin caused by a vacuum formed by a whirlwind
snubnose brotula; armoured cusk (Hoplobrotula armata)
ferret badger (esp. the Chinese ferret-badger, Melogale moschata)
false indigo (Amorpha fruticosa); bastard indigo; leadwort
goatsbeard brotula (species of ophidiiform fish, Brotula multibarbata)
tiger shark (Galeocerdo cuvier)
鼬 combines 鼠 (rat/mouse) with 由, which likely contributes the sound. The character denotes a weasel-like animal, a member of the rodent-like mustelid family.
The left side 鼠 suggests a rodent-like creature, and the right side 由 (reason) hints at the reason for its smell: a weasel or skunk. Picture a mouse-like animal with a distinctive musky reason for its reputation.
For ユウ, imagine a weasel letting out a long 'yuuu' sound as it scurries away: yuuu -> ユウ.