It's a dirty great ball (5)
I believe the answer is:
earth
'dirty great ball' is the definition.
The definition and answer can be both to do with contact as well as being verbs in their base form.
Perhaps you can see an association between them that I can't see?
'it's a' is the wordplay.
I cannot quite see how this works, but
'a' is found in the answer.
'it' could be 't' (abbreviation. e.g. in 'tis) and 't' is located in the answer.
This explanation may well be incorrect...
Can you help me to learn more?
(Other definitions for earth that I've seen before include "Our favourite planet" , "The 3rd planet from the sun" , "Fox's burrow" , "It is necessary to clear" , "Soil; electrical ground" .)