Negative fear and lacking faith vs positive fear

Deilos (Strong’s 1169) = negative fear of timidity is contrasted with phobos – positive fear (Strong’s 5401 mentioned re’ fear of God etc)

It is linked to a lack of faith (pistei):

Mt 8:26, Mk 4:40 – why afraid, men of little faith?

Rev 21:8: Deilos and unbelieving (a-pisteos) folk are assigned to the a second death.