A poombasnort is an involuntary spasm that releases tension built up before and during the interview. It is often aimed towards the interviewer scaring them from ever hiring you for that job as they fear you may have something mentally wrong. A poombasnort can also affects ones speech (see example)
This is also a word that can be used after a particularly rubbish day.
"Not great, i did a poombasnort"
"Aw that's too bad!"
"So i'll look forward to hearing from you" = "MPF MFHS"
"Well that was a poombasnort of a day!"