From WordNet dictionary, version 3.0:
hoot
n. 1. a loud raucous cry (as of an owl)
2. a cry or noise made to express displeasure or contempt
Synonyms: boo, Bronx cheer, hiss, raspberry, razzing, razz, snort, bird
3. something of little value; "his promise is not worth a damn"; "not worth one red cent"; "not worth shucks"
Synonyms: damn, darn, red cent, shit, shucks, tinker's damn, tinker's dam
v. 1. to utter a loud clamorous shout; "the toughs and blades of the city hoot and bang their drums, drink arak, play dice, and dance"
2. utter the characteristic sound of owls