“Idiom” and “idiot” [closed]

Question

The words idiom and idiot differ only in the final letters: t and m. So I was wondering - do these words have a common root? If so, how have the t and m changed this root?

Answer 1

I suspect this may be general reference, but from the OED:

Etymology of idiot:

ancient Greek ἰδιώτης private person, person without professional knowledge, layman, ignorant, ill-informed person, in Hellenistic Greek also common man, plebeian < ἴδιος private, own, peculiar (see idio- comb. form) + -ώτης -ote suffix

Etymology of idiom:

Hellenistic Greek ἰδίωμα peculiarity, property, peculiarity of style, form of language peculiar to a particular individual < ancient Greek ἰδιοῦσθαι to make one's own, to appropriate ( < ἴδιος own, private, peculiar: see idio- comb. form) + -μα (see -oma comb. form).

So it appears that they share a very distant root (idio-) but their meanings would have been distinct even in ancient Greece by virtue of the endings.