Déclore belong to the 3
rd group.
Déclore is conjugated the same way that verbs that end in :
-ore
Déclore is conjugated with
auxiliary avoir.
Déclore is a defective verb.
It can not be conjugated in all possible forms.
Déclore verb is
direct transitive.
Déclore verb is a direct transitive verb, so passive voice can be used.