1. [20C+] nonsense, lies.
2. [1910s+] (also bull manure) rubbish, anything second-rate or useless.
3. [1920s+] an object or task that is seen as annoying, irritating or ‘nonsense’.
4. showing off.
5. [1970s] an argument.
6. [1970s] (US drugs) marijuana.
7. [1970s+] used metonymically to characterize a person.
[1940s+] anyone with a good line of persuasive, if insincere patter.
[1940s+] (N.Z.) Air Force headquarters, then subseq. Parliament.
see bull session n.