1. One who trims, arranges, fits, or ornaments. 2. One who does not adopt extreme opinions in politics, or the like; one who fluctuates between parties, so as to appear to favor each; a timeserver. Thus Halifax was a trimmer on principle. Macaulay. 3. An instrument with which trimming is done. 4. (Arch.) A beam, into which are framed the ends of headers in floor framing, as...