What is the difference between ‘keep’ and ‘keep on’? The meanings of ‘keep’ and ‘keep on’ are very similar and can be used as synonyms. In many circumstances ‘keep’ and ‘keep on’ can be used interchangeably, however, there is a difference that dictates whether or not to use ‘keep on’ or simply ‘keep’.
‘Keep’ is a very common word in the English language. Most commonly used a verb, it can be transitive or intransitive. It means to continue to have or hold something securely and not lose, sell, give away, throw away or return something. For example: Keep the gift I gave you. It can also mean to continue or cause something to continue in a certain state, condition or position. For example: Keep walking, don’t slow down. ‘Keep’ also can take on the meaning of observing, celebrating or commemorating something important. For example: Keep this day special. It stresses the idea of not neglecting or violating. A ‘keep’ as a noun is related to the meaning of not letting something go and holding it safe and secure. It is an old-fashioned word that means the strongest part of a castle that provides protection.
‘Keep on’ is a phrasal verb using the verb form of ‘keep’. It is commonly used with a gerund clause, which contains a verb used as a noun ending in –ing. Used this way, it has the meaning of continuing on or persist in doing something without any intention of stopping. Some examples: Keep on walking, keep on moving, keep on coming. When used in this sense, it is an intensive version of ‘keep’ that means to continue in a state, condition or position, and the ‘on’ is added for emphasis. Because of this, ‘Keep on’ is often used in idioms. For example, the saying ‘keep on keeping on’ means to continue working at something, usually life or surviving in general. For example: Keep on keeping on, Mary, don’t give up because you got one bad grade in school.
‘Keep on’ can have another usage. Also as a phrasal verb it can mean to allow something to remain in a place or position. It is often used in this way to refer to keeping something, such as clothing, on or in place. For example: I can’t keep on a sweater in the summer, because I get too hot. It has the connotation of both not wanting something on, not being able to maintain something, or something not staying on because it falls off or out of its proper place. For example: She can’t keep on weight since she started growing so fast. In this meaning it can also be used to refer to someone keeping the position of a job. For example: We keep the gardener on to ensure the roses look nice. This usage is rather out of fashion in American English and not commonly used, rather more often used in British English.