(verb) PE Boyz equivalent to calling someone, or occaisionally an event, 'a twat'. The word is used only in certain circles and many are oblivious when hummed. An individual may hum another should they deem a particular action or event warrants it. An person or event warranting a hum is said to be humworthy.
An alternative to the traditional hum is that of 'Huh?.....mmm'
Occasionally the word may be used in the adjective to described an often hummed individual or for an event that recieves many hums.
The effort I have gone to to explain the word is humworthy. I should indeed recieve a hum. Huh?......mmm