rarefy - Dictionary definition and meaning for word rarefy
rare-fy rare ~ low in density (therefore thin, sparse) -fy is a root means "to make". you "make" something "thinner" is rarefy.
rarely is anyone thin these days
rare+fy(fry)=> if we will fry something it will become weaken
THIN people are RARE these days
forests become LESS DENSE => animals become RARE