1. [late 16C+] (also barsterd) a contemptible, objectionable person.
2. [1910s+] (orig. Aus.) a general term for a man, a person or any form of creature or thing; not esp. derog.; e.g. lucky bastard.
3. [1910s+] (orig. Aus.) a term of man-to-man affection; often as old bastard
4. [1920s+] an admirable person, creature or object.
5. [1930s+] (orig. Aus.) a situation, a circumstance, usu. a problematic one.
6. [1930s+] an object.
[1940s+] a general intensifer, a modified version of fucking adj. (1)
[1950s] a general term of abuse.
[1920s–50s] a general intensifier, completely, extremely, very much.
[1970s+] a general intensifier, usu. with adj.
[1990s+] (Aus.) to commit oneself unrestrainedly.
[20C+] (orig. Aus.) a phr. for anything considered unpleasant, excessively challenging etc.
[1910s+] (orig. US) a general intensifier; often with lie or work.
[late 19C+] a man, often used as a term of affectionate address.