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An act is 'actionable' if it is capable of being pursued as a legal action in the civil courts. Not all wrongs suffered by an individual are actionable. For example, if I were to visit your home while you were undergoing a debilitating emotional crisis, and I were to then persuade you to give me money so that I might leave, this blatant exploitation by me of your vulnerable state of mind would probably not be actionable. It would certainly be underhanded and immoral; but not every immoral act is thereby 'actionable'.

Generally speaking, there is some vague correspondence between the terms 'actionable' and 'unlawful'.