who is a leech?

'I know the whole argument against welfarism. Welfarism is a dirty word in Singapore. No! We are a meritocratic society! We survive and prosper on hard work and our own efforts! If we allow for welfarism we will have leeches in our society feeding off the wealth of those who had worked hard for their achievements. '

The above is quoted from coffee and cigarette blog.

When I read this term '