Operational or operative.
One adjective based on the related noun is operational. It has the adverb form operationally.
The adjective form of concept is conceptual.The adjective form of conception is conceptional.
The adjective form is cranial.
The word is the same. The context in which it is used as an adjective can relate to an intention to save money, to describe something costing less to buy or operate or in relation to 'economy class' when travelling.Another answer:The adjectival form of 'economy' is 'economic' or 'economical'. The previous answer describes the use of the noun as a quasi-adjective, which is not the same thing.
The Adjective form of Pathologist is Pathological.
The adjective form of concept is conceptual.The adjective form of conception is conceptional.
The adjective form of improve is "improved."
The adjective form for the pronoun they is their.
The adjective form for the verb to develop is developable.
The plural form of the noun 'adjective' is adjectives.
The adjective form of retire is :- retired, retiring.
The adjective form is patient.