Tim Bowen explains the origin and different meanings of this word. It's mint!
The word mint has two distinct meanings in English. The first, derived from Greek through Latin mentha, is the small aromatic plant that also gives us words for different kinds of sweets (e.g. peppermints, spearmints) and the word menthol.
The second word comes from the Latin moneta, which is also the source of the English word money, and is a place where coins are produced or minted. In the case of the United Kingdom, this is the Royal Mint, which is located near Cardiff in South Wales and which mints the different coins in use in the UK. This meaning of mint also gives us the expression 'in mint condition', meaning in new or perfect condition, an expression often used to describe second-hand goods for sale. 'In mint condition' has now given rise to a new use of mint in modern British colloquial usage as an adjective meaning 'great, fantastic, brilliant'. It is particularly common in the Geordie dialect of Newcastle in the North-East of England. An example of this would be “I really enjoyed the gig last night. It was mint!”