Source : Webster's Revised Unabridged Dictionary (1913)

Miff \Miff\, n. [Cf. Prov. G. muff sullenness, sulkiness, muffen
   to be silky, muff["i]g sullen, pouting.]
   A petty falling out; a tiff; a quarrel; offense. --Fielding.

Miff \Miff\, v. t.
   To offend slightly. [Colloq.]

Source : WordNet®

miff
     n : a state of irritation or annoyance [syn: {huff}, {seeing red}]
     v : cause to be annoyed; "His behavior really miffed me"