meaning of "write off"


Could you tell me the ,meaning of “write somebody off” as in this context:
I[color=red] wrote her off for the 10th time today
And practiced all the things I would say
When she came over I lost my nerve
I took her back and made her desert
I know I should say no

Thanks !


'Write off ’ suggests to me discount/disregard/not worth considering/considering of no value. A car after a serious accident is 'written off ’ by an insurance company if they consider it is not worth repairing where the cost of repair is more than its actual value.