From The Jargon File (version 4.4.7, 29 Dec 2003):
CLM
/C·L·M/
[Sun: ‘Career Limiting Move’]
1. n. An action endangering one's future prospects of getting plum projects
and raises, and possibly one's job: “His Halloween costume was a parody of
his manager. He won the prize for ‘best CLM’.”
2. adj. Denotes extreme severity of a bug, discovered by a customer and
obviously missed earlier because of poor testing: “That's a CLM bug!”