'our social and economic goal' Part of speech of the underlined word is

The word 'and' joins two adjectives ('social' and 'economic') that both modify the noun 'goal'. Words that join words, phrases or clauses are conjunctions. 'And' is the most common coordinating conjunction. It is not a pronoun (doesn't replace a noun), not a determiner (doesn't specify a noun), and not an interjection (no exclamation).