Eavesdropping is the act of secretly listening to conversations without the knowledge of the people involved. It is often done by placing a listening device near a window or other opening in a building, hence the term 'EAVESDROPPING'. The term 'EAVESDROPPING' is derived from the Old English word 'eavesdroppan', which means 'to drop from the eaves'. ICICLE is an appropriate crossword solution for the term 'EAVESDROPPING' as it refers to the icicles that form on the eaves of a building when it is cold outside.