Root س ف ه(s f h) has 6 unique word forms and appears 11 times in the Quran.

English gloss Stupid, Foolish, Incompetent

Word Translation Occurrences
ٱلسُّفَهَآءُ (are) the fools, the foolish, the foolish ones 6
سَفَاهَةٞ foolishness 2
سَفِهَ fooled 2
سَفَهَۢا (in) foolishness 2
سَفِيهًا (of) limited understanding 2
سَفِيهُنَا the foolish among us 2
ٱلسُّفَهَآءَ the foolish 2
سَفَاهَةٖ foolishness 2
ٱلسُّفَهَآءُۗ the fools 2