The Lord is just in all his ways, and kind in all his doings. The Lord is near to all who call on him, to all who call on him in truth. He fulfils the desire of all who fear him; he also hears their cry, and saves them. The Lord watches over all who love him, but all the wicked he will destroy. (Psalm 145: 17-20)

To be wicked - rasha' - is to live outside the community, to be self-interested, and treat others with disinterest or worse. It is a verb.

Wickedness -resha' - is a masculine noun for someone who behaves in these ways. In Hebrew the noun and the verb are spelled the same.

Even in English I am far from a grammarian. But isn't wicked used above as a noun: the wicked? If so shouldn't this be wickedness?

In every translation I have accessed, it is consistently translated as wicked, not as wickedness. But it is also always treated as a noun.

If the Hebrew is truly a noun, it seems the translation would be "but all wickedness he will destroy."

If the Hebrew is truly a verb, I think the translation would be something like "but all sinning he will stop."

In any case, one way I hope the Lord is watching over me is to destroy my wickedness.

Part of the challenge here is the English use of wicked. In English it is almost always an adjective. But it is a very good parallel term with rasha'/resha'. In Old English the wike was the village or almost any boundary. To be wicked was to come from outside the village or behave in a manner outside accepted boundaries.