rou4 has two components . The first component is nei meaning 'inside' (originally written with meaning 'small area'-'enter') and the second component is ren2 meaning 'man' (a stick figure of a walking person). What is inside man is 'flesh' or 'meat'.
rou4ma3 means 'nauseating' or 'disgusting' and literally translates as 'flesh'-'numb' i.e. goose-pimples.
ma can also be written as which breaks down into and means 'sickness in forest' (the two 'trees' make up a forest). 'Numbness' is akin to the eerie feeling one gets when one is lost in a forest.
gu3rou4 means 'offspring' and literally translates as 'bone'-'flesh' i.e. of my bone and flesh.
in ancient script
looks very much like a skeleton. Some etymologists deemed its origins to
meaning 'scraped flesh' i.e. only bones left.