Exclude previous morning's law test (3,4)
I believe the answer is:
bar exam
'law test' is the definition.
'bar exam' can be an answer for 'test' (I have seen 'professional test' mean 'bar exam' so perhaps 'test' could also mean 'bar exam'). I am not certain of the 'law' bit.
'exclude previous morning's' is the wordplay.
'exclude' becomes 'bar' (synonyms).
'previous' becomes 'ex' (prefix meaning former or onetime).
'morning' becomes 'am' (as in 12:00 AM).
'bar'+'ex'+'am'='BAR EXAM'
Can you help me to learn more?
(Another definition for bar exam that I've seen is " professional test".)