half-step

Short definition from Wiktionary

Noun

1. 1
   Alternative form of half step.
2. 2
   The distance between two tones. In 12-tone equal temperament, its frequency ratio is 2^(1/12), or about 1.059 or 18/17.

Verb

1. 1
   To back down from; fail to follow through or complete; to be slack
2. 2
   To fail to display full commitment, preparation, or genuineness; to be a poser; to be a fake or fraud