remarkable
unregular
unwontedly
rare as hen's teeth
atypical
uncommonly
seldomness
unusualness
sporadic
regularity
periodically
sporadically
uncommon
strange
unusuality
unruleful
roughly
eternally
out of the way
different
out of the common
geason
unequal
episodic
aleatorily
incessantly
anomalistic
forever
perpetually
always
lippening
constantly
randominity
offbeat
dys-
antrin
episodicity
para-
spontaneous
isanomal
malformation
subregular
everyday
randomwise
distinctive feature
rare as a four-leaf clover
whacking
miscreation
distinguishing characteristic
peculiarity