NOUN (1)

1. a group's refusal to have commercial dealings with some organization in protest against its policies;


VERB (1)

1. refuse to sponsor; refuse to do business with;

The Collaborative International Dictionary of English v.0.48:

Boycott \Boy"cott`\, v. t. [imp. & p. p. Boycotted; p. pr. &
   vb. n. Boycotting.] [From Captain Boycott, a land agent in
   Mayo, Ireland, so treated in 1880.]
   To combine against (a landlord, tradesman, employer, or other
   person), to withhold social or business relations from him,
   and to deter others from holding such relations; to subject
   to a boycott.
   [1913 Webster]

The Collaborative International Dictionary of English v.0.48:

Boycott \Boy"cott\, n.
   The process, fact, or pressure of boycotting; a combining to
   withhold or prevent dealing or social intercourse with a
   tradesman, employer, etc.; social and business interdiction
   for the purpose of coercion.
   [1913 Webster]

WordNet (r) 3.0 (2006):

boycott
    n 1: a group's refusal to have commercial dealings with some
         organization in protest against its policies
    v 1: refuse to sponsor; refuse to do business with [ant: buy
         at, frequent, patronise, patronize, shop, shop
         at, sponsor]