muser vs ponderer

muser and ponderer both are nouns.

Word	Noun	Adjective	Verb	Adverb
muser	Yes	No	No	No
ponderer	Yes	No	No	No

As nouns, muser and ponderer are synonyms defined as:

muser and ponderer: a reflective thinker characterized by quiet contemplation

Other synonyms of muser include muller, ruminator.

muser (noun)	ponderer (noun)
a reflective thinker characterized by quiet contemplation	a reflective thinker characterized by quiet contemplation