Wuss is a term which is roughly synonymous with words like sissy or wimp, and is in common use in most english speaking countries. The 'u' is pronounced like the 'u' in 'push'. Usually prefaced with the word 'bloody' as an emphatic.
Wuss is a pretty tame insult, even more tame than wimp and sissy, and is used liberally by Australian fathers in their quests to toughen up their children.
e.g. "Is it broken? Then stop blubbering, ya bloody wuss!"