… double parking in front of one in street (4)
I believe the answer is:
spit
'double' is the definition.
(as in a 'spitting image')
'parking in front of one in street' is the wordplay.
'parking' becomes 'p' (abbreviation on road signs).
'in front of' means one lot of letters go next to another (some letters go in front of others).
'one' becomes 'i' (Roman numeral).
'in' is an insertion indicator.
'street' becomes 'st' (abbreviation).
'p'+'i'='pi'
'pi' going inside 'st' is 'SPIT'.
(Other definitions for spit that I've seen before include "Eject saliva - roasting rod" , "Expectorate on the tongue of land" , "Expectorate on the tongue of sand" , "Expectorate, or a long thin metal spike" , "Skewer -- exact likeness" .)