The term 'stiff ride' can be solved by the 6-letter word 'HEARSE'. A HEARSE is a vehicle used to transport a deceased person's body from a funeral service to a cemetery. It is typically a long, black vehicle with a flat back and a glass partition between the driver and the passengers. The term 'stiff ride' is often used to describe the uncomfortable ride of a HEARSE due to its lack of suspension and its large size.