| coexisting |
| coextensive |
| cogent(clear, sound, reasonable, sensible, rational) |
| cognate(joint, linked, combined, homogeneous, cooperative) |
| collective(joint, linked, combined, homogeneous, cooperative) |
| commensurable |
| commonsensical(clear, sound, reasonable, sensible, rational) |
| compelling(clear, sound, reasonable, sensible, rational) |
| complete(adjective, united) |
| concerning(important, significant, consistent, compatible, applicable) |
| concerted(joint, linked, combined, homogeneous, cooperative) |
| concord |
| condign |
| confederated(joint, linked, combined, homogeneous, cooperative) |
| conformant(important, significant, consistent, compatible, applicable) |
| conjoint(joint, linked, combined, homogeneous, cooperative) |
| conjugate(joint, linked, combined, homogeneous, cooperative) |
| conjunctive(joint, linked, combined, homogeneous, cooperative) |
| consequent(clear, sound, reasonable, sensible, rational) |
| consolidated(joint, linked, combined, homogeneous, cooperative) |