footling vs niggling

footling and niggling both are adjectives.

Word	Noun	Adjective	Verb	Adverb
footling	No	Yes	No	No
niggling	No	Yes	No	No

As adjectives, footling and niggling are synonyms defined as:

Other synonyms of footling include fiddling, lilliputian, little, petty, picayune, piddling, piffling, trivial.

footling (adjective)	niggling (adjective)
(informal) small and of little importance	(informal) small and of little importance