IM or in , and EM or EN .
The prefix in is from the Latin, and that of en from the French and Greek. In generally signifies situation, and en mostly expresses action. Hence, perhaps, in strictness, inclose will signify “to close in,” and enclose, “to make close.” So, to inquire will be “to seek in, or to search in,” and enquire, to “make search.” Immigrate, “to pass into;” emigrate, “to go out of.” But this distinction is not attended to by writers, and is, indeed, too refined for general practice.
Before the letters b and p, en becomes em, as in embattle, empower; and in before some letters becomes ig, il, im, or ir, as in ignoble, illegal, improper, irresolute.
We give a list of those generally spelt with im or in; leaving it to be inferred that the rest are more usual with em or en.
imbarn
imbibe
imboil
imbound
imbrue
imbrute
imbue
imburse
immanacle
immense
immerge
immerse
immigrate
immingle
immit
immix
immure
impact
impale
imparadise
impassioned
impawn
impeach
impearl
impel
impen
imperil
impinge
implant
implead
import
impose
impound
impregnate
impress
imprint
imprison
inarch
incase
inclasp
inclip
incloud
include
incrassate
increase
incur
indart
indent
indict
indite
indoctrinate
indrench
induce
induct
ineye
infer
infest
inflix
inflame
inflate
inflect
inflict
infringe
infuscate
infuse
ingrane
ingest
inhabit
inhale
inhere
inhold
inhume
initiate
inject
inlapidate
inlay
inlet
inoculate
inosculate
inquire
inrail
inscribe
insculp
inseam
insert
inset
inshell
inship
insinew
insphere
inspire
inspirit
install
instate
insteep
instil
instop
insure
inter
intertwine
intort
intreasure
intrench
intrude
intrust
inumbrate
inure
inurn
invade
inveigh
invert
invest
invigorate
invite
invocate
invoice
invoke
inwall
inweave