From The Collaborative International Dictionary of English v.0.48 :
Belligerence \Bel*lig"er*ence\, Belligerency \Bel*lig"er*en*cy\,
n.
The quality of being belligerent.
[1913 Webster]
2. the act or state of being engaged in war or a warlike
conflict; warfare.
Syn: hostilities.
[WordNet 1.5]
3. an aggressively hostile or warlike attitude or nature; a
readiness to fight or offend, with little or no
provocation.
[WordNet 1.5 +PJC]
From WordNet (r) 3.0 (2006) :
belligerency
n 1: hostile or warlike attitude or nature [syn: belligerence,
belligerency]
2: fighting; acts of overt warfare; "the outbreak of
hostilities" [syn: hostilities, belligerency]