adjective. Extremely poor behaviour of a person or persons. To be bad mannered and hostile in the extreme. To have few or no manners, or little to no upbringing.
Origin of word - From the town where this behaviour seems to be the norm.
Example 1 -
Jeff - 'She was hungry and all she asked was when they were going to get something to eat, and that's when he shouted "Oh, stop whinging, you idiot! For Christ's sake!"'
Bob - 'But she's so sweet and lovely! Why was he so Grantham to her?'
Example 2 -
Alice -'...and when he said he couldn't understand why people would prefer to watch a rape scene in a soap opera to watching Star Wars, she bellowed "God! Stop whining! Shut your bloody mouth!" right in front of all his friends! Poor fellow was stunned!'
Jenny - 'I'm not surprised! Embarassing him in front of his friends? What awful and Grantham behaviour! She ought to be ashamed of herself!'
Alice - 'Being so Grantham, she probaly has no idea what is, let alone have any...'