No, except perhaps in a poetic context. The reason that the adjective 'deft' can't be used to describe a 'festivity' is because deft describes an ability to perform with dexterity, cleverness, or skill. A festivity has no abilities and it can't perform; a festivity is a thing.
Suppose that the festivity was deftly achieved? The word 'deftly' is an adverb, modifying the verb 'achieved'.
Festivity is a noun.
The abstract noun forms of the adjective 'festive' are festiveness and festivity.
The noun forms for the verb attach are attachment and the gerund, attaching.
The word 'Halloween' is a proper noun, the name of a specific festivity held annually on the night of October 31.
Deft - adj Quick and skillful
she decided to go to Dr. dude because of reputation as a deft doctor. deft means skillful.
A deft person is a quick and skillful person, usually dexterous.
The base word of "deftly" is "deft." "Deft" means skillful and quick in one's movements or actions.
With his deft hands he could work a puzzle very quickly.
file leter by deft //d6 notice send?
Deft means to demonstrate cleverness and skills and it means neatly quick and skillful in a person's movements. He was admired because of his deft handling of problems in the office.
She relaxed completely while the deft fingers of the masseuse massaged her body.