noun

1. the vertical clearance above someone's head, as in a tunnel, doorway etc

1. (electronics) the ability of a system to reproduce loud sounds free of distortion; dynamic headroom

abbreviation

1. (Internet) have fun

noun

1. high fidelity

noun (abbreviated as hi-fi or HiFi?)

1. An electronic system that reproduces a given sound or image with relatively high accuracy

adjective

1. (context, of a sound system) characterized by minimal distortion

noun

1. A tune created orally with lips closed.
   
2. An often indistinct sound resembling that produced by humming.

verb (hum, m, ing)

1. To make a sound from the vocal chords without pronouncing any real words, with one's lips closed.
2. : To smell bad.
3. : To deceive, or impose on one by some story or device.