The opposite of "quality" (of fine material or construction) would be inferiority or shoddiness.
The opposite of quality papers would be poor or low-quality papers.
good quality
good quality
expensive opulent, expensive, pricy, highbrow,
low mortals least value
The opposite of a lofty quality would be a mundane or ordinary quality.
For comparing quality, the opposite of "premier" (superior) could be inferior or poor. Where premier assumes the very best, the opposite is worst or poorest.
The opposite of better (improved, superior) is worse.A similar words for "of a lesser quality" would be inferior.
For most meanings of good, the opposite is bad, or possibly awful.For good meaning "benevolent" the opposite would be evil(malevolent).For good meaning "acceptable in quality" the opposite would be poor.For good meaning "fresh" the opposite would be spoiled or gone bad.In other applications, the opposite could be unacceptable, unsuitable, or useless.
Durable good
Opposite by definition; " Having a position on the other or further side of something." Polar opposite, is essentially the opposite of something that is of the further* side. Ergo, all polar opposites are opposites, but not all opposites are polar. For example: Word: Famous (Known about by many people) A polar opposite: Infamous (Well known for some bad quality or deed) Ordinary opposite Unknown (Not known or familiar) In summary, a polar opposite, is an opposite of the word within the same 'field' if you will.
No. The only conditions to quality as a parallelogram is that it is a quadrilateral, and that opposite sides are parallel.