well ok just for the record they are two different words
shoddy is a method of reclaiming used wool (clothes etc)
they grind it up and mix it with fresh wool giving a hard wearing wool cloth
mungo is a related term which uses off cuts which hasnt been used in a similar process but producing a much higher quality of cloth (the developer of shoddy couldnt use the off cuts his nephews developed mungo)
basically because of the Napoleonic wars and the trade embargoes britain was struggling to get enough wool for our production needs and so this was a response to make cheap wool which need less new wool to produce and was of a hardwearing construct
it is usually discussed as "shoddy and mungo" because the process and suppliers were the either the same or very similar
the slang use of shoddy comes from the poor quality materials used in this mass produced product so things that were made of poor quality picked up the shoddy name and its expanded a bit since
:-p who else wants to "present" some weird words
