The term 'CERTAIN SWINGER' is composed of two words, 'CERTAIN' and 'SWINGER'. The first word, 'CERTAIN', is an adjective meaning 'DEFINITE' or 'SURE'. The second word, 'SWINGER', is a noun referring to a person who enjoys social activities such as dancing, partying, and engaging in sexual activities. The crossword solution for this term is 'HINGE', which is a mechanical device that allows a door or window to open and close. Hinges are used to connect two objects together, allowing them to move in relation to each other.