Cases of word usage

1) doing the duties of another person for a limited time (acting)

2) the process of doing things, using energy, influence etc (action)

3) doing things; able to do things; in the habit of doing things (active)

4) expressing regret for doing wrong or not doing something (apologetic)

5) to say one is sorry (for doing wrong or not doing something) (apologize)

6) a statement of being sorry (for doing wrong or not doing something) (apology)

7) out of, off, the right path, especially into doing wrong (astray)

8) to make repayment (for doing wrong) (atone)

9) (speaking, doing something) for another person or group (behalf)

10) a part of a sentence with its own subject and predicate, especially one doing the work of a noun, adjective or adverb (clause)