Chigau and erai (exalted, high, distinguished): 違う vs. 偉い.
also: 彼 and 席 and 度 . . . (kare, seki, and do) mean respectively "he," "seat," and "time" (as in iti-do simasu -- I did it one time.)
I CANNOT KEEP THEM STRAIGHT AND NEVER HAVE BEEN ABLE TO DO SO.