unstudied (adj.)

• ad-lib
• affable
• artless
• automatic
• casual
• colloquial
• common
• conversational
• cordial
• degage
• easy
• easygoing
• everyday
• extemporaneous
• extemporary
• extempore
• familiar
• folksy
• gracious
• haphazard
• hasty
• homely
• homey
• ill-advised
• ill-considered
• impromptu
• improvised
• inadvertent
• informal
• ingenuous
• involuntary
• irregular
• loose
• makeshift
• naive
• natural
• nonstandard
• offhand
• offhanded
• plain
• precipitate
• reflex
• reflexive
• relaxed
• rough-and-ready
• simple
• sociable
• spoken
• spontaneous
• spur-of-the-moment
• substandard
• surprised
• unadvised
• unaffected
• unassuming
• unceremonious
• unconscious
• unconsidered
• unconstrained
• uncontrived
• unconventional
• undesigned
• uneducated
• unexplored
• unhatched
• unintended
• unintentional
• unliterary
• unmade
• unofficial
• unorganized
• unplanned
• unpremeditated
• unprepared
• unready
• unrehearsed
• unschooled
• unsophisticated
• untutored
• unwilled
• vernacular