If delete tv show on my MacBook does it delete it from iTunes account?

I keep getting the message that my start up disk is almost full. So, I found out that it is because of the tv shows I have on my iTunes library. So, if I delete the ones I already watched, are they deleted from my iTunes library? Since I paid for the Season, I think I should have access anytime I want to, but need to clear my start up disk. What shoud I do?