Sentence:  These booze customers had until then been buying their supplies from the Sheldon , Saltis-McErlane , and Druggan-Lake gangs , and now they were competing for trade with the Torrio-Capone saloons ; once again O ' Banion 's brash recklessness had <WSD>caused</WSD> a proliferation of ill will . 
Meaning of the word marked with <WSD> tags:  give rise to; cause to happen or occur, not always intentionally