You see, I've seen the word "rationalism" used to mean all five of these things at different times:
- The belief that we should come to know the world through reason and experimentation, shunning intuition.
- The belief that we should come to know the world through reason and intuition, shunning experimentation.
- The belief that we should come to know the world through knowledge of (and correction for) cognitive biases, and knowledge of (and correct use of) probability theory.
- Being effective at believing things that are true and not things that are false.
- Being effective at doing things that are good and not things that are bad.
Edited to reinstate that proposed solution, since this discussion is presumably finished.
"LessWrongism" is more likely to stick.