- in force
- innards
- inlet
- ink-pad
- injunction
- injection
- in fun
- irregularly
- initially
- initial release
- inhume
- inheritor
- inheritance
- inharmonious
- inhale
- inhabitable
- ingratitude
- ingrained, engrained
- ice-cold
- idealist
- ideology
- ingenuous
- idol
- ingenious
- if
- ignominious
- ilk
- ill-advised
- illusory
- illustrious
- imbalance
- immaculate
- informal
- impale
- impinge
- implacable
- implication
- impolitic
- impose oneself
- impossible
- irrational number
- impostor
- infliction
- impromptu
- improvise
- impurity
- inflammatory
- inadequate
- incivility
- inappreciable
- incline
- incognito
- iron deficiency anaemia
- incensed
- inception
- incidence
- incomparably
- indefinable
- independent
- indicated
- indication
- indiscreet
- indistinguishable
- industrious
- infested
- inexpensive
- inexplicable
- infatuated with joy
- infantry
- infiltrate
- inflate
- infatuated person
- informed
- infancy
- infamous
- inexact
- inherent
- inhibit
- inessential
- injudicious
- insistent
- instalment
- instant
- instigator
- instinct
- instruction
- instructor
- instrumental
- insubordinate
- inertia
- intense
- intensive
- inedible
- intrigue
- invalid
- inventory
- irrecoverable
- isolated
- in a jiffy
- indubitable