The ROOT-WORD is the Suffix ISH. It means ORIGIN as in No. 11, IrISH; NATURE, as in No.10, amateurish, RESEMBLING, as in No.9, clownISH. In the last two there is an uncomplimentary element. Usually ISH makes adjectives of nouns. Sometimes verbs have this Suffix for no apparent reason, as perISH, nourISH, etc.