Uncombinable is a word that describes things that cannot be mixed or merged together. Antonyms for uncombinable, then, would be words that describe things that can be successfully mixed, combined, or merged. These antonyms could include words such as compatible, harmonious, cohesive, integrated, connected, blended, amalgamated, fused, united, and synchronized. These words describe things that work well together, that can be combined to form a whole that is greater than the sum of its parts. Whether we are talking about ideas, people, or objects, these antonyms for uncombinable describe things that are able to work together, to form a greater whole.