Definition of uncharacteristic adjective from the Oxford Advanced Learner's Dictionary

uncharacteristic

adjective
ˌʌnˌkærəktəˈrɪstɪk
 
; ˌʌnˌkærəktəˈrɪstɪk
 
 
uncharacteristic (of somebody) not typical of somebody; not the way somebody usually behavesThe remark was quite uncharacteristic of her.
Opposite
characteristic
uncharacteristically
ˌʌnˌkærəktəˈrɪstɪkli
 
; ˌʌnˌkærəktəˈrɪstɪkli
 
adverbThe children had been uncharacteristically quiet.