- informal make head or tail of
- in extremis
- in-your-face
- in the meanwhile
- in the blood
- in times gone by
- ima-ginative
- inspirational
- infirmities
- in all respects
- intermit
- in olden times
- improperly
- I haven't the faintest notion
- in unity
- in the ascendancy
- individualized
- indocrinate
- informal park
- infra dig
- inch
- interdependent
- integument
- in the know about
- imperceptibly
- in all instances
- informal soft-soap
- in spite of that
- indelicacy
- imagined
- in raptures
- iron-fisted
- in the genes
- Ingra-tiating
- ill repute
- it would seem
- idioms
- infuriated
- in the midst of in the course of
- in one's genes
- in league
- inconsistently
- in re
- ideal place
- incomparability
- in a hurry
- intending
- in an instant
- in a delicate condition
- informl tatty
- in a position to
- in bygone days
- impinge on
- involuted
- ill breeding
- invest in
- inspirit
- in the affirmative
- initialize
- invariability
- in-depth
- immoderateness
- in next to no time
- impanel
- immolation
- in a pickle
- in a class of its own
- illumining
- intelligencer
- in store
- I haven't the foggiest idea
- in confusion
- in contrast with
- in one's cups
- insipidity
- iconoclastic
- indoctrination
- in a state of nature
- in the picture
- in a flap
- informal terribly
- inebriety
- in the know
- indistinguishability
- informal be the boss of
- in vogue
- in good spirits
- injudiciousness
- impotence
- in captivity
- irresoluteness
- idealized
- incontrovertibly
- I'll say
- ill-informed
- intercessor
- ineradicable
- in disagreement with
- immutably
- in an acting capacity