Insist on Definition 1 of 3Pro Tip 1/3Strong Determination Expresses a firm decision that isn’t open for negotiation or discussion. He insists on attending the meeting in person. Pro Tip 2/3Possible Irritation Sometimes used to imply someone is being stubborn or irritating in their demands. She insists on blaring her music late at night. Pro Tip 3/3Expect Resistance Used when someone may face opposition or reluctance, but remains firm. Despite our doubts, he insists on investing in that idea.