Field of legislation's some bearing (4)
I believe the answer is:
lawn
'field' is the definition.
(lawn is a kind of field)
'legislation's some bearing' is the wordplay.
'legislation' becomes 'law' (I've seen this before).
'some bearing' becomes 'n' (**).
'law'+'n'='LAWN'
'of' acts as a link.
(Other definitions for lawn that I've seen before include "Stretch of grass" , "Fine fabric" , "Linen fabric" , "Type of thin linen or cotton" , "Area of smooth grass - fine linen" .)