Clothe, the least specific of these terms, means to cover or to provide what will cover (one’s body or whatever is bare) with or as if with garments. The other words convey the same meaning but each one adds to it distinctive implications and connotations.
Attire suggests a more careful process and more formality than clothe and therefore is avoided except when the context requires that note.
Dress is far less formal than attire and much richer in its connotations than clothe. It often suggests care in the choice and arrangement of clothes and sometimes, especially in dress up, preening and prinking or selection of one’s best or choicest clothes.
Dress up sometimes distinctively implies an assuming of the dress of or a dress suitable to another while dress, especially in its intransitive or reflexive forms, often implies a change of clothes to those that are appropriate for a special occasion; thus, to dress for dinner implies a change into dinner or evening clothes.
The idea of decking or adorning is frequently associated with dress especially in its extended senses.
Apparel and array are chiefly literary words used when there is the intent to connote splendor, elegance, or gorgeousness in what a person or thing is clothed with.
Robe implies a dressing with or as if with a robe and has the same wide range of use as the noun but it typically suggests the enveloping apparel worn by a king, queen, or noble on state occasions, by a judge or a professor when the conventions of his office demand it, or by a bishop or other high ecclesiastic when formally but not liturgically attired.