Deem/diːm/ Definition 1 of 3Pro Tip 1/3Subjectivity Using 'deem' shows the speaker's personal judgment or opinion on a matter. She deemed the solution inadequate. Pro Tip 2/3Authority 'Deem' is often used when someone with authority makes a judgment or decision. The committee deemed the proposal acceptable. Pro Tip 3/3Formality 'Deem' is formal and frequently appears in official contexts or documents. The act was deemed unlawful by the court.