Farrah Abraham -- Pleads NOT GUILTY to DUI

Farrah Abraham has pleaded NOT GUILTY to her DUI -- and her May 31st trial could be awesome ... based on her list of excuses.

TMZ broke the story ... the former MTV "Teen Mom" (turned porn star) got popped for DUI in Nebraska, back in March.

Farrah's attorney was in court this morning to enter a not guilty plea to all 3 charges she's facing -- aggravated DUI, refusal to take a field test and disorderly conduct.

Farrah blew a .147 -- nearly twice the legal limit, according to the police report.

She went on TMZ Live days after the arrest and claimed she did nothing wrong -- that people had been feeding her drinks ... she was "put in a bad situation" by her sister ... was only re-parking her car ... she had a sober friend with her ... plus she had a bad cough and couldn't blow properly.

Tell it to the judge, Farrah.