fanciful

In this rosy way of thinking, Trump won’t ever stand for election again and has a legacy to consider — a fanciful notion that is plainly a triumph of hope over experience.

You argue that the very notion of the marketplace of ideas is itself so utterly fanciful and corroded that the notion that we just take away constraints and the good ideas unerringly rise to the top has to be insane, right?

Talk of the Golden Boot might have been fanciful at the start of the season but Wood is currently in that bracket.

He added the suggestion police should not have spoken about the case was "fanciful".

Half a century ago, such ideas were received by the scientific community as speculative at best and fanciful at worst.