Akrasia
Procrastinator
ThirdWizard said:Ad hoc:
"Ad hoc is a Latin phrase which means "for this [purpose]." It generally signifies a solution that has been tailored to a specific purpose, such as a tailor-made suit, a handcrafted network protocol or a specific-purpose equation, as opposed to general solutions. It can also refer to an improvised and often impromptu event or solution "on an ad-hoc basis", as opposed to well-prepared ones."
http://en.wikipedia.org/wiki/Ad_hoc
"Something that is ad hoc or that is done on an ad hoc basis happens or is done only when the situation makes it necessary or desirable, rather than being arranged in advance or being part of a general plan. [3]"
http://www.ee.oulu.fi/research/ouspg/sage/glossary/
I'm well aware of the meaning of the term 'ad hoc'. Which is precisely why I think that the term is inaccurate.
The application of general principles to specific cases is not 'ad hoc'. Yet it also does not require extensive specific rules.