“JITTERIER” is a valid word.

retirego into retirement; stop performing one's work or withdraw from one's position
ritter
jittersmall rapid variations in a waveform resulting from fluctuations in the voltage supply or mechanical vibrations or other sources
triterrepeated too often; overfamiliar through overuse
terret
territ
trijet

treea tall perennial woody plant having a main trunk and branches forming a distinct elevated crown; includes both gymnosperms and angiosperms
tirehoop that covers a wheel
ritean established ceremony prescribed by a religion
tiera relative position or degree of value in a graded group
tititree of low-lying coastal areas of southeastern United States having glossy leaves and racemes of fragrant white flowers
jeershowing your contempt by derision
jete
retea network of intersecting blood vessels or intersecting nerves or intersecting lymph vessels
tret

tieneckwear consisting of a long narrow piece of material worn (mostly by men) under a collar and tied in knot at the front
jetan airplane powered by one or more jet engines
ere
titeither of two soft fleshy milk-secreting glandular organs on the chest of a woman
teethe starting place for each hole on a golf course
errto make a mistake or be incorrect
rei
tetthe New Year in Vietnam; observed for three days after the first full moon after January 20th
jee
ree
irea strong emotion; a feeling that is oriented toward some real or supposed grievance
retplace (flax, hemp, or jute) in liquid so as to promote loosening of the fibers from the woody tissue

itthe branch of engineering that deals with the use of computers and telecommunications to retrieve and store and transmit information
era trivalent metallic element of the rare earth group; occurs with yttrium
rea rare heavy polyvalent metallic element that resembles manganese chemically and is used in some alloys; is obtained as a by-product in refining molybdenum
et
tia light strong grey lustrous corrosion-resistant metallic element used in strong lightweight alloys (as for airplane parts); the main sources are rutile and ilmenite

JITTERIER