1. a person who commits or perpetrates an act, especially a crime or offense
Usage: often used in legal or formal contexts
2. a person who is dedicated or pledged to a cause, belief, or relationship
Usage: common in social and personal contexts
3. in software development, a person who submits code changes to a repository
Usage: technical jargon; used in programming and version control contexts

Examples

• The committer of the robbery was arrested after a two-week investigation.
• She is a committer to environmental causes and volunteers regularly.
• The committer pushed the new feature to the main branch yesterday.
• Police identified the committer through DNA evidence.
• He proved to be a true committer to the team's mission.
• Each committer in the project must follow the coding standards.