Following are all the impromptus like words, in the list below.
AD LIB
100% like impromptus
SPUR-OF-THE-MOMENT
99.99% like impromptus
SPONTANEOUSLY
99.79% like impromptus
AD LIBITUM
99.78% like impromptus
UNPREPARED
99.61% like impromptus
EXTEMPORANEOUS
50.06% like impromptus
OFF-THE-CUFF
50.06% like impromptus
AD-HOC
50.06% like impromptus
IMPROVISED
50.06% like impromptus
MAKESHIFT
49.91% like impromptus
SPONTANEOUS
49.86% like impromptus
TEMPORARY
49.84% like impromptus
INTERIM
49.84% like impromptus
ADLIB
49.82% like impromptus
HASTY
49.79% like impromptus
UNPREDICTABLE
49.79% like impromptus
UNFORESEEABLE
49.69% like impromptus
UNSOLICITED
49.6% like impromptus
INFORMAL
49.59% like impromptus
PROVISIONAL
48.89% like impromptus
IMPRIMIS
0.12% like impromptus
IMPULSION
0.12% like impromptus
IMPETUSES
0.12% like impromptus
UNPROMPTED
0.12% like impromptus
IMPOSTS
0.12% like impromptus
IMPULSIVE
0.12% like impromptus
IMPARIPINNATE
0.12% like impromptus
IMPASSION
0.12% like impromptus
SPONTOON
0.12% like impromptus
IMPULSES
0.12% like impromptus
IMPULSIVITY
0.12% like impromptus
SPONTANEITY
0.12% like impromptus
IMPULSIVENESS
0.12% like impromptus
IMPLEX
0.12% like impromptus
IMPETUOUS
0.12% like impromptus
INSTANTS
0.12% like impromptus
IMPREST
0.12% like impromptus
IMPOSTHUME
0.12% like impromptus
INDISCRETE
0.12% like impromptus
IMPETUOUSNESS
0.12% like impromptus
IMPARITY
0.12% like impromptus
IMPULSIVELY
0.12% like impromptus
IMPRECISION
0.12% like impromptus
PROMPTITUDE
0.12% like impromptus
SPONTANEOUSNESS
0.12% like impromptus
IMPUTATIONS
0.12% like impromptus
PROMPTS
0.12% like impromptus
IMPREGNATION
0.12% like impromptus
PROPOSITI
0.12% like impromptus
IMPATIENS
0.12% like impromptus
IMPARTER
0.12% like impromptus
IMPRECISE
0.12% like impromptus
IMPERFORATE
0.12% like impromptus
IMPROBABLE
0.12% like impromptus
IMPUNE
0.12% like impromptus
IMPUTER
0.12% like impromptus
IMPELS
0.12% like impromptus
REMIGES
0.12% like impromptus
IMPLEADER
0.12% like impromptus
INFINITIVES
0.12% like impromptus
IMPRESE
0.12% like impromptus
IMPONE
0.12% like impromptus
INSTANTANEOUS
0.12% like impromptus
IMPENITENCE
0.12% like impromptus
IMPETIGINOUS
0.12% like impromptus
IMPRESCRIPTIBLE
0.12% like impromptus
INSTANT
0.12% like impromptus
INSTANTANEITY
0.12% like impromptus
PROMPTNESS
0.12% like impromptus
IMPROVISATORY
0.12% like impromptus
INTUITIVE
0.12% like impromptus
INTUITIONS
0.12% like impromptus
IMPOSTURE
0.12% like impromptus
TRAPES
0.12% like impromptus
IMPOSTORS
0.12% like impromptus
INSTANTER
0.12% like impromptus
IMPIS
0.12% like impromptus
SOLITAIRES
0.12% like impromptus
IMPETUOUSLY
0.12% like impromptus
INDITES
0.12% like impromptus
IMMEDIACY
0.12% like impromptus
IMPUDENTLY
0.12% like impromptus
IMPRECISENESS
0.12% like impromptus
IMPETUOSITY
0.12% like impromptus
INEXPLICIT
0.12% like impromptus
IRRESISTIBLE IMPULSE
0.12% like impromptus
PROPOSITUS
0.12% like impromptus
IMPONDERABLES
0.12% like impromptus
MONOCHAMUS
0.12% like impromptus
PASSERES
0.12% like impromptus
INFINITIVAL
0.12% like impromptus
IMMEDIATENESS
0.12% like impromptus
IMPASSIONATE
0.12% like impromptus
CAPRICES
0.12% like impromptus
GRATUIT
0.12% like impromptus
CONJUGANT
0.12% like impromptus
PASQUIN
0.12% like impromptus
INADVERTENCE
0.12% like impromptus
UNSCRIPTED
0.12% like impromptus
IMPOSTERS
0.12% like impromptus