Question

what was the meaning of being morden according to French in vietnam

Answer 1

in simple words,

So the french in Vietnam wanted to make the people modern.In order to do that they gave the people of Vietnam a modern education but the French thought that in order to learn "modern education" , the Vietnams should also be modern

So the french made a rule for the Vietnams to chop off their original long hair and introduced modern games,outfits to them.