When it comes to painting or applying something on a surface, the phrase "smear on" is commonly used. However, there are several synonyms that can be used to convey the same meaning. The word "smudge" is often used to describe a smeared or blurred image or make-up. Another synonym for smear on is "spread on," which is commonly used in food-related contexts when applying butter or jam on bread. The verb "daub" can also replace smear on, particularly when describing the application of paint or clay. Additionally, words such as "coat," "cover," and "apply" can be used as synonyms for "smear on" depending on the context.