insight vs brainwave

insight and brainwave both are nouns.

Word	Noun	Adjective	Verb	Adverb
insight	Yes	No	No	No
brainwave	Yes	No	No	No

As nouns, insight and brainwave are synonyms defined as:

insight and brainwave: the clear (and often sudden) understanding of a complex situation

Other synonyms of insight include brainstorm.

insight (noun)	brainwave (noun)
grasping the inner nature of things intuitively	the clear (and often sudden) understanding of a complex situation
the clear (and often sudden) understanding of a complex situation	(neurophysiology) rapid fluctuations of voltage between parts of the cerebral cortex that are detectable with an electroencephalograph
clear or deep perception of a situation
a feeling of understanding