As adjectives the difference between riffier and niffier
is that riffier is (riffy) while niffier is (niffy).
riffier
English
Adjective
(head)
(riffy) riffy
English
Adjective
(er)
(music) Characterized by a lot of riffs (guitar riffs) niffier
English
Adjective
(head)
(niffy) niffy
English
Adjective
(er)
(colloquial) Having a bad smell.
Synonyms
* (having a bad smell ):
** (standard ): fetid, stinking
** (colloquial/slang ): pongy, stinky, whiffy