The antonym for "do take off" can be "keep on." To "do take off" means to remove something or to start something, whereas "keep on" means to continue doing something without stopping. For example, if someone says, "Please do take off your shoes before entering the house," the antonym of that sentence would be, "Please keep on wearing your shoes." Another example would be if someone says, "I'm going to do take off work early today," the opposite would be, "I'm going to keep on working the full day today." When using antonyms, it is important to understand the context of the sentence to pick the right opposite meaning.