From TheReincarnation

Units that attack with a paralyze attack type stops the counterattack of the target defending units.

Example:
A has paralyze ability
B is any unit

• A attacks B
  
• A deals damage and paralyzes B
  
• B counters and gets fatigued but will not do damage
  

Notes

• There is also a phantasm spell called Paralyze which should not be confused with the attack type mentioned here