This is the same word as Choppy in Chinese but in practice the Rough pulse is a variation of the Choppy pulse.  A Rough pulse is a Choppy pulse that hits many different places on the diagnosing finger, sometimes feeling as though it is approaching the finger from many different angles.  This indicates that the volume of mediumship (Blood or Fluids) has decreased enough to allow Wind to enter the channel, causing instability.  

Feels like: The Rough pulse feels as though a ball point pen is tapping at your finger from a different angle and landing at a slightly different spot on the finger at every strike.