snogging vs fondling

snogging and fondling both are nouns.

Word	Noun	Adjective	Verb	Adverb
snogging	Yes	No	No	No
fondling	Yes	No	No	No

As nouns, fondling is a hypernym of snogging; that is, fondling is a word with a broader meaning than snogging:

snogging: (British informal) cuddle and kiss
fondling: affectionate play (or foreplay without contact with the genital organs)

Other hypernyms of snogging include caressing, cuddling, hugging, kissing, necking, petting, smooching, snuggling.

snogging (noun)	fondling (noun)
(British informal) cuddle and kiss	affectionate play (or foreplay without contact with the genital organs)