tor
insinuator
institutor
instructor
interlocutor
interpolator
interrogator
inventor
investor
juror
lector
legator
legislator
lessor
mediator
modulator
monitor
mortgagor (_law_)
multiplicator
narrator
navigator
negotiator
nonjuror
numerator
objector
obligor (_law_)
observator
operator
originator
pacificator
participator
peculator
percolator
perforator
perpetrator
persecutor
perturbator
possessor
preceptor
precursor
predecessor
predictor
prevaricator
procrastinator
procreator
procurator
professor
progenitor
projector
prolocutor
promulgator
propagator
propitiator
proprietor
prosecutor
protector
protractor
purveyor
recognizor (_law_)
recriminator
reflector
regenerator
regulator
relator (_law_)
rotator
sacrificator
sailor (_seaman_)
scrutator
sculptor
sectator
selector
senator
separator
sequestrator
servitor
solicitor
spectator
spoliator
sponsor
successor
suitor
supervisor
suppressor
surveyor
survivor
testator
tormentor
traitor
transgressor
translator
valuator
vendor (_law_)
venerator
ventilator
vindicator
violator
visitor

IV

Words which in their shortest form end in _-d_, _-de_, _-ge_, _-unit_,
_-rt_, _-se_, _-sr_, take the ending _-sion_; e.g., _abscind_,
_abscission_; _include_, _inclusion_; _emerge_, _emersion_; _remit_,
_remission_; _infuse_, _infusion_; _repress_, _repression_.

All others take the ending _-tion_.

The following are irregularities:

adhesion
assertion
attention
coercion
cohesion
crucifixion
declension
dimension
dissension
distortion
divulsion
expulsion
impulsion
insertion
intention
occasion
propulsion
recursion
repulsion
revulsion
scansion
suspicion
tension
version

Words ending in _-ance_, _-ence_; _-ancy_, _-ency_; _-ant_, and _-ent_,
often cause confusion when carelessly written.

The following is a list of the more common words with the _e_ form.

abducent
abhorrence, -ent
abluent
absent, -ence
absorbent
abstergent
abstinence, -ent
adherence, -ent
advertency, -ent
affluence, -ent
antecedence, -ent
apparent
appertinent
appetence, -ency
ardent
benevolence, -ent
circumference
coexistence
coherence, -ent
coincidence, -ent
competence, -ent
concurrence, -ent
condolence
conference
confidence, -ent
confluence, -ent
consentient
consequence
consequent
consistence, -ent
consistency
constituent
continence, -ent
convenience, -ent
corpulence, -ent
correspondence, -ent
cur