"Blow it off" is an informal term that refers to ignoring or dismissing something. There are several different synonyms to use in place of this phrase, depending on the context. Some alternatives include "brush it aside," "disregard," "overlook," or "discount." Each of these terms conveys a similar meaning of ignoring or downplaying something. Other options may include "shrug it off" or "let it go," which imply a willingness to move on from the matter at hand without giving it further attention. Ultimately, the appropriate synonym to use will depend on the situation and the tone or style of communication being conveyed.