spine-tinglingˈspine-ˌtingling adjective 
making you feel very excited or frightened, in an enjoyable way: 
The festival opened with Nic Roeg’s latest spine-tingling film.
making you feel very excited or frightened, in an enjoyable way: The festival opened with Nic Roeg’s latest spine-tingling film.- free-falling
- free-floating
- Freefone
- underwent
- underwhelm
- underworld
- underwrite
- underwriter
- Underwriters' Laboratories
- undeserved
- undesirable
- undetected
- undeterred
- undeveloped
- undid
- undies
- undifferentiated
- undignified
- undiluted
- undiminished
- undischarged
- undisclosed
- undiscriminating
- undisguised
- undismayed