guff (guf), n. Slang.
1. empty talk; nonsense.
2. back talk; lip.

nick (nik), n.
1. a place where a small bit has been cut or broken out; notch; groove.
2. Priniting. a notch in the shank of a type, that serves as a guide to the identification of a font or the placing of the types.
3. the precise moment or time of some occurence.
4. British Slang. a jail; prison.
5. Australian. condition; shape.
6. Obsolete. the exact point aimed at; mark.
in the nick of time, just at the right moment.
--v.t.,
1. to make a nick or nicks in; notch or chip.
2. to cut into or through.
3. to hit, guess, catch, etc., exactly.
4. a. to make an incision at the root of (a horse's tail) to cause him/her to hold it higher.
4. b. to cut (a horse) at the root of the tail.
5. to record or score
6. Slang. to cheat; defraud.
7. Slang. to capture, especially by surprise; nab.
[origin uncertain]

Nick (nik), n. Usually, Old Nick. the Devil.
[probably short for Nicholas. Compare German Nickel goblin.]

[Courtesy
Merriam-Webster's Collegiate Dictionary,
Tenth Edition. ]