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1.
A mature cheddar head is someone who is very mature but acts really stubborn and stuck-up with it, quite snobby. They are mature in a really boring way with no sense of humour and take everything seriously.
'Sophie told me making fart noises is immature.'
'Don't worry, she's a mature cheddar head with no sense of humour.'
by mousey1306 March 07, 2012