malfunctioning vs defective

malfunctioning and defective both are adjectives.

Word	Noun	Adjective	Verb	Adverb
malfunctioning	No	Yes	No	No
defective	No	Yes	No	No

malfunctioning (adjective)	defective (adjective)
not performing or able to perform its regular function	markedly subnormal in structure or function or intelligence or behavior
	having a defect
	not working properly