unplanned

adjectives

without apparent forethought or prompting or planning
"an unplanned economy"; "accepts an unplanned order"; "an unplanned pregnancy"; "unplanned remarks"
unplanned
antonym
planned
is similar to
occurring or appearing or singled out by chance
"seek help from casual passers-by"; "a casual meeting"; "a chance occurrence"
casual, chance
is similar to
often improvised or impromptu
"an ad hoc committee meeting"
ad hoc
is similar to
without or seeming to be without plan or method; offhand
"a casual remark"; "information collected by casual methods and in their spare time"
casual
is similar to
not prepared or planned in advance
"asked an unpremeditated question"
unpremeditated
see also
not deliberate
unintended
not done with purpose or intent
"an unintended slight"; "an unintentional pun"; "the offense was unintentional"; "an unwitting mistake may be overlooked"
unintentional, unplanned, unwitting