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