It's an actual word. Look it up.
Rather expectedly, a stinkaroo is something of markedly inferior quality. It sounds funny, but it's an effective word into today's marketplace.
I've had to use this word during pitches in the past. It not only adds a much needed layer of playfulness in a high stress situation, but it also allows me to be pinpoint honest without immediately hurting anyone's feelings.
It may be an enjoyable word to hear phonetically, but trust me, you should avoid hearing the intent behind it during your professional career at all costs.