JITTER - is a valid Scrabble word.
Definition of JITTER:
- fluctuations in the image on a television screen or in copy received by facsimile transmission, caused by interference or by momentary failures of synchronization
- nervousness; a feeling of fright or uneasiness (usually prec. by the)
- to behave nervously
- to fidget (to move about restlessly) [v -ED, -ING, -S]