Auto suggest in user field

I have created my own column to indicated the genre of a book. I manually enter the names such as "mystery" or "suspense" or "Alt History." All are one or two word entries.

From time to time I mis-type an entry. Thus the program will suggest:
Mysgtery
Mysery
Mystery
and such like that.

Is there any way to purge the erroneous suggested entries, or even all entries?

Sincere thanks