"with penetrating understanding into character or hidden nature," 1881, from insight + -ful. Some earlier words in the same sense were insighted (c. 1600), inseeing "having insight" (1590s). Related: Insightfully; insightfulness.
an insightful parent
inside
inside-out
insider
insidious
insight
insightful
insignia
insignificance
insignificant
insincere
insincerity
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