Happening or appearing now and then
Rarely occurring or appearing
His nobles, whom he tried to cow by sporadic acts of violence, rebelled against him.
But the failures were sporadic only.
On the other hand, German sporadic attacks by sea and air on British watering places and the increasing activity of German submarines gave Mr. Churchill and the Admiralty much concern.
Someone beat on the door across the hall loud enough for Bianca to hear over the TV and sporadic thunder.