a·mor·phous [? máwrf?ss] adjective 1. without shape: without any clear shape, form, or structure 2. not classifiable: not obviously belonging to any category or type 3. chemistry geology not crystalline: without a crystalline structure [Mid-18th century. Via modern Latin < Greek amorphos "without shape" < morph? "shape"] -a·mor·phous·ly, adverb -a·mor·phous·ness, noun