A practice test taken orally with no control? (4)
I believe the answer is:
amok
'with no control?' is the definition.
(as in to run amok)
'a practice test' is the wordplay.
'practice' becomes 'mo' (abbreviation for modus operandi).
'test' becomes 'k' (I can't justify this - if you can you should believe this answer much more).
'a'+'mo'+'k'='AMOK'
'taken orally' acts as a link.
I am not very happy about this link. Some or all of it may be part of another bit of the clue.
(Other definitions for amok that I've seen before include "(Run) in murderous frenzy" , "Run (disruptively out of control)" , "(Run) wild, out of control" , "Going mad" , "Running wild" .)