Fat cats oddly ignored decree from parliament (3)
I believe the answer is:
act
'decree from parliament' is the definition.
'act' can be an answer for 'decree' (I've seen this before). I'm not certain of the 'from parliament' bit.
'fat cats oddly ignored' is the wordplay.
'oddly ignored' means one should take alternating letters (letters in odd-numbered positions are removed).
'fat'+'cats'='fatcats'
The alternate letters of 'fatcats' are 'ACT'.
Can you help me to learn more?
(Other definitions for act that I've seen before include "Perform(ance)" , "Do something, in a play?" , "performing group" , "Assumed attitude" , "work" .)