The verb IR means "to go". It is USUALLY followed by the preposition "a" (unless otherwise specified; ej. ir de compras).
IR is the only verb in Spanish that does not fit into the category of an -ar, -er, or
Though IR is considered an IRREGULAR verb, meaning that it does not follow any "regular" pattern, it does resemble -ar verb endings. All forms will start with the letter "v" and the "YO" form will end in "oy" instead of just "o".