خَائِفٌ is the active participle, “one who fears”; مَخُوفٌ is the passive participle, “one/that which is feared.” Each has six principal masculine and feminine number/gender forms.
PositionActive participlePassive participle
Masc. singularخَائِفٌمَخُوفٌ
Masc. dualخَائِفَانِمَخُوفَانِ
Masc. pluralخَائِفُونَمَخُوفُونَ
Fem. singularخَائِفَةٌمَخُوفَةٌ
Fem. dualخَائِفَتَانِمَخُوفَتَانِ
Fem. pluralخَائِفَاتٌمَخُوفَاتٌ
These are semantically distinct: the fearer must not be confused with the object of fear.