Turn aside rule in official piece of legislation (7)
I believe the answer is:
refract
'turn aside' is the definition.
'refract' can be an answer for 'turn' (thesaurus). I'm not certain of the 'aside' bit.
'rule in official piece of legislation' is the wordplay.
'rule' becomes 'r' (abbreviation for rule).
'in' means one lot of letters goes inside another.
'official' becomes 'ref' (match official in football, say).
'piece of legislation' becomes 'act' (I've seen this in another clue).
'ref'+'act'='refact'
'r' put within 'refact' is 'REFRACT'.
Can you help me to learn more?
(Other definitions for refract that I've seen before include "Change light's direction" , "Change direction of light, eg, in water/glass" , "Bend ray of light as it meets glass or water" , "(Of lens) change direction of (light beam)" .)