| Term | Definition |
| concord | agreement |
| concourse | a crowd |
| concur | to agree |
| condescend | to lower oneself to an inferior's level |
| condign | deserved |
| condiment | seasoning |
| condolence | expression of sorrow |
| condone | to excuse |
| conducive | tending to or leading to |
| conduit | pipe or tube through which fluid or electricity passes |
| confidant | a trusted friend |
| configuration | shape |
| confiscate | to seize by way of penalty |
| conflagration | a large and destructive fire |
| confluent | merging |
| conformity | agreement; doing the same as others |
| confounded | confused |
| congeal | to freeze solid |
| congenial | friendly |
| congenital | existing at birth |