- unthinkable
- unthinkableis still used in its original meaning ‘unable to be imagined or grasped in the mind’:
• You wander…in cool glades of unthinkable beauty —Westminster Gazette, 1897.
But far more common now is the extended and more evaluative meaning ‘too unlikely or absurd to be considered’, comparable to similar shifts that have occurred with unimaginable and inconceivable:• In these circumstances the removal of British troops was unthinkable —C. Allen, 1990
• What is known about the clergyman's honesty and integrity would have made such an act unthinkable —Contemporary Review, 2003.
Despite Fowler's objections to this use (as an expletive without the necessary ‘aroma of brimstone’) in a lengthy and ultimately futile tirade (1926), it is a natural development that retains the essence of the original meaning and applies it in a more realistic way, since nothing that is postulated can be literally ‘unthinkable’. Fowler knew this and saw in it the word's appeal, but common usage has taken a more practical course. To think the unthinkable means to consider ideas or possibilities usually regarded as too disturbing or undesirable to be contemplated. It originated in the 1960s as the title of a book (Thinking about the Unthinkable) by Herman Kahn about the prospect of a nuclear war.
Modern English usage. 2014.