The antonyms for the expression 'something put aside' can be diverse and depend on the specific context. However, possible antonyms for this phrase could be 'something at hand,' 'something in use,' 'something needed,' or 'something present.' These antonyms imply that the object is not stored, ignored, or neglected, but rather of immediate importance or relevance. For instance, if someone puts books aside, the antonym could be to keep them at hand for future reference or to use them in ongoing studies. Similarly, if someone sets aside a project, the antonym could be to prioritize it and work on it without delay.