tall story
Concise Oxford English Dictionary © 2008 Oxford University Press:
tall/tɔːl/
▶adjective of great or more than average height.
■ measuring a specified distance from top to bottom.
– phrases
a tall order an unreasonable or difficult demand.
tall story (or tale) an account that is fanciful and difficult to believe.
a tall order an unreasonable or difficult demand.
tall story (or tale) an account that is fanciful and difficult to believe.
– derivatives
tallish adjective,
tallness noun.
tallish adjective,
tallness noun.
– origin ME (in senses ‘swift, prompt, fine, handsome’, and ‘bold, strong’): prob. from OE getæl ‘swift, prompt’.
'tall story' also found in these Oxford entries:

