1) Accidental 2) Ad hoc 3) Casual 4) Chance 5) Unexpected 6) Unintended 7) Unpremeditated 1) Accidental 2) Catch as catch can 3) Cchascchcan 4) Chance 5) Impulsive 6) Random 7) Unintended 8) Unintentional 9) Unpremeditated 10) Unprepared 11) Unwitting 
[adj] - without apparent forethought or prompting or planning
adjective without apparent forethought or prompting or planning; `an unplanned economy`; `accepts an unplanned order`; `an unplanned pregnancy`; `unplanned remarks`