What is the difference between yellow urine and clearish urine?

Relative dilution. The gradient of colorless -> yellow urine is based, among other factors, on the relative dilution of the excreted waste. Increasing intake of water leads the kidneys to excrete more water for the same amount of excreted waste thereby diluting urine color to be lighter "clearish". Vitamin intake also makes urine yellow. Please note, "clearish", vs cloudy, is a different issue with different causes.
Dilution. Color is mostly a reflection of level of hydration. Some medications or supplements (vitamin b) can also effect color.