Caffiend

1 - A person hopelessly addicted to caffeine

2 - A person who has consumed caffeine to the point of becoming non-functional

1 - "Dude, it's 10am and that's like your fifth cup of coffee!" "I know, I'm a caffiend and cannot function without it."

2 - "Dude! Did you see Rhonda? She talking 93 mph and started dancing in her cube!" "Yeah... She's a caffiend today."