| clean-timbered |
| clean up |
| clean up one's act |
| clear blue water |
| clear cut |
| clear off |
| clear one's lines |
| clear the air |
| clear the table |
| click into gear |
| climb down |
| climb the walls |
| clip it |
| clip someone's wings |
| clitlicker |
| clock in |
| clock is ticking |
| clock the tea |
| clog up |
| close, but no cigar |
| closed book |
| close enough for government work |
| close in on |
| close one eye |
| close one's eyes |
| close one's eyes and think of England |
| close one's mind |
| close on the heels of |
| close season |
| closet case |
| close the book on |
| close the books |
| close the face |
| close the stable door after the horse has bolted |
| close to home |
| cloth |
| cloud nine |
| cloud seven |
| clusterfuck |
| clutch artist |
| cobbler, keep to your last |
| cockblock |
| cock cheese |
| cock of the roost |
| cock of the walk |
| coffee talk |
| coil up |
| cold chills |
| clothespin vote |
| cloud-headed |
| clout list |
| clue stick |
| clutches |
| coals to Newcastle |
| cock-and-bull story |
| cock a snook |
| cock in the henhouse |
| cock off |
| cock one's toes |
| coffee money |
| coke dick |
| cold cash |
| cold comfort |
| cold day in Hell |
| cold fish |
| cold hand |
| cold hard cash |
| cold-livered |
| cold one |
| cold shoulder |
| cold snap |
| cold treatment |
| cold turkey |
| collect dust |
| collect one's thoughts |
| comb-out |
| comb through |
| come a cropper |
| come across |
| come again |
| come alive |
| come along |
| come a long way |
| come apart at the seams |
| come around |
| come back from the dead |
| come clean |
| come down |
| come down in stair rods |
| come down to |
| come down to earth |
| come down to us |
| comedy gold |
| comedy of errors |
| come first |
| come forward |
| come from a Cracker Jack box |
| come from a good place |
| come full circle |
| come hell or high water |