Profit and nonprofit corporations, Massachusetts trusts, associations, trusts, general partnerships, joint ventures, limited partnerships, and governments and governmental subdivisions, agencies, or instrumentalities may not plead the defense of usury nor maintain any action thereon or therefor, and persons may not plead the defense of usury nor maintain any action thereon or therefor if the transaction was primarily for agricultural, commercial, investment, or business purposes: PROVIDED, HOWEVER, That this section shall not apply to a consumer transaction of any amount.
Consumer transactions, as used in this section, shall mean transactions primarily for personal, family, or household purposes.