This dirty world of ours (5)

I believe the answer is:

earth

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'this dirty world' is the definition.
'earth' can be an answer for 'world' (synonyms). I am unsure of the 'this dirty' bit.

I can't explain the remainder of the clue.

Can you help me to learn more?

(Other definitions for earth that I've seen before include "hideaway" , "Human world" , "Terra firma" , "Soil; electrical ground" , "Connection between an electrical device and conductor" .)

I've seen this clue in the Evening Standard.

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