important
significant
alternate
beating
circling
consequential
cyclic
even
every other
far-reaching
intermittent
isochronal
measured
metronomic
momentous
oscillatory
periodical
pulsing
reciprocal
recurrent
recurring
rhythmic
rotary
seasonal
serial
steady
undulant
undulatory
unmatched
unparalleled
wavelike
wheeling
all-or-nothing
attitudinal
cancer-causing
cataclysmic
dissoluble
education/non-profit
ejaculatory
inerrable
life-altering
life-changing
mehow
millenarian
mirth-provoking
nephrotoxic
pre-arranged
pro-war
psychohistoric
resectable
shallow-minded
teratogenic
world-shaking
world-shattering