Ariel Winter's Mom -- I Called Attorney a 'Moron' Because ...

Chrystal Workman is defending the verbal lashing she gave an attorney as a gut reaction to her daughter Ariel Winter being taken from her ... TMZ has learned.

TMZ broke the story ... during a guardianship hearing for the "Modern Family" star last month ... Chrystal yelled at Ariel's guardianship attorney and called her a "moron."

Sources close to the family tell us Chrystal was very upset because she felt like lies were being spewed in court about her parenting and she was fed up ... as she claims any mother would be.

As one source put it, "If someone were trying to take your child that you loved more than anything else away from you, wouldn't you react in a similar way?"

We're told Chrystal apologized in court shortly after the outburst.

As for why Chrystal waited 2 weeks to notify the Sheriff's Department -- about allegedly catching 14-year-old Ariel and the boyfriend in a sexual situation ... we're told she thought she could handle it privately like any other parent.

But we're told she thought she had no other choice after the guardianship hearing ... because she felt like Ariel -- and her older daughter Shanelle -- had ambushed her in court.