The antonyms for the word "under-cutting" are many and varied, ranging from positive to negative. Some of the most commonly used antonyms for "under-cutting" include "supporting," "uplifting," "encouraging," "strengthening," "helping" and "promoting." Conversely, some of the more negative antonyms for "under-cutting" are "impeding," "hindering," "obstructing," "preventing," and "weakening." Depending on the context and usage, a particular antonym may be more appropriate than others. Regardless, it is important to weigh the pros and cons of certain actions or behaviors to better understand if they are helping or harming a particular situation.