The term 'spread thickly' can be solved by two crossword solutions, SLATHER and PLASTER. SLATHER is a verb meaning to spread a thick layer of something, usually a liquid or semi-liquid substance, over a surface. It is often used in reference to food items such as butter, cream, or sauces. PLASTER is also a verb meaning to spread a thick layer of something, usually a dry material such as cement or PLASTER, over a surface. Both terms are commonly used in construction and home improvement projects.