1. most lacking in refinement, sophistication, or good taste; most vulgar or offensive
2. most basic, simple, or primitive in form or development
3. most unprocessed or in natural state

Examples

• His crudest jokes made everyone uncomfortable at the dinner party.
• The crudest tools were made from stone and wood.
• That was the crudest attempt at an apology I’ve ever heard.
• The crudest oil requires extensive refining before use.
• She used only the crudest materials to build her shelter.
• His crudest behavior emerged when he was angry.
• The crudest estimates suggest the project will take months.