Meanings of mitigatory in English

My dear boy, learn this grand truth now: That philosophy is never satisfactory; it is only mitigatory.

From 1905 on they were in decided opposition to the existing system, and were revolutionary rather than merely mitigatory organizations.

As construction projects gain pace once again, there is an accelerating demand for suitably trained, qualified and experienced archaeologists to undertake necessary mitigatory works.

I thought initially that these were offences which justified a jail sentence, but the mitigatory circumstances would have converted that to a suspended sentence.