ski vs wedel

ski is a noun but wedel is not a noun.

Word	Noun	Adjective	Verb	Adverb
ski	Yes	No	Yes	No
wedel	No	No	Yes	No

As verbs, wedel is a hyponym of ski; that is, wedel is a word with a more specific, narrower meaning than ski:

Other hyponyms of ski include hot-dog, schuss, slalom, water ski.

ski (noun)	wedel (noun)
narrow wood or metal or plastic runners used in pairs for gliding over snow

ski (verb)	wedel (verb)
move along on skis	ski, alternating directions