1. affording grounds for legal action

- slander is an actionable offense

Similar word(s): unjust

2. that can be acted on; that can be used as the basis for taking action.

Sentences with actionable as an adjective:

- I'm sure it's not good of me to write that he's a lush, but is it actionable?

- Clearly the libelous book is actionable, but I'm not commenting on anything to do with legal issues.