Clue: Mocking learner after Day One — car breaks down around lunchtime (9)
Answer: SATIRICAL
Explanation: Definition: Mocking
A charade of SAT ('day') plus I ('one') plus RICA, an envelope ('around') of I (1pm., ;lunchtime') in RCA, an anagram ('breaks down') of 'car'; plus L ('learner', with the position of this particle being suggested by 'after').