| | CFNM | | clothed females, naked male |
| | CFNM | | clothed females, naked males |
| | CFNM | | clothed male, nude female |
| | CFO | | Chief Financial Officer |
| | CFR | | Cost and Freight |
| | CFS | | call for service |
| | CFS | | Covered Full Service |
| | CFV | | Call For Votes |
| | CFV | | call for voting |
| | CFYD | | Computer Fine User Drunk |
| | CGI | | common gateway interface |
| | cgip | | computer graphics and image processing |
| | CGYOFM | | can't get you off my mind |
| | CGYOOMH | | Can't Get You Out Of My Head |
| | cgyoomm | | can't get you out of my mind |
| | CGYT | | Cat Got Your Tongue |
| | chown | | change owner |
| | CHTML | | compact HTML |
| | CHUD | | Cannibalistic Humanoid Underground Dwellers |
| | CHUI | | CHaracter User Interface |
| | CIA | | Cash In Advance |
| | CIA | | Central Intelligence Agency |
| | CIAC | | Computer Incident Advisory Capability |
| | CIBM | | Could It Be Magic? |
| | CIC | | Christ I'm Confused |
| | CIDR | | classless inter-domain routing |
| | CIF | | Cash In First |
| | CIF | | Cost Insurance , Freight |
| | CIFS | | Common Internet File System |
| | CIH | | Cash In Hand |
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