The word budget is it a noun or proper noun?

The Word 'budget' is a noun, a verb, and an adjective.

The noun 'budget' is a common noun, a general Word for an estimate of income and expenditure for a set period of time; a general Word for a plan for using money; a general Word for a written statement of income and expenditure.

A proper noun is the name or title of a specific person, place, or thing.

The noun forms of the verb to budget are budgeter, bugeteer, and the gerund, budgeting, which are common nouns.