" Have - have you got an appointment?' he said.
'I don't know,' said Carrot. 'Have we got an appointment?'
'I've got an iron ball with spikes on,' Nobby volunteered.
'That's a morningstar, Nobby.'
'Is it?'
'Yes,' said Carrot. 'An appointment is an engagement to see someone, while a morningstar is a large lump of metal used for viciously crushing skulls. It is important not to confuse the two, isn't it, Mr-?' He raised his eyebrows.
'Boffo, sir. But-'
'So if you could perhaps run along and tell Dr Whiteface we're here with an iron ball with spi- What am I saying? I mean, without an appointment to see him? Please? Thank you. "

― Terry Pratchett , Men at Arms (Discworld, #15; City Watch #2)