Olympian has dropped American underwear, plain lot in black and white (6)
I believe the answer is:
zebras
'plain lot in black and white' is the definition.
I can't judge whether this defines the answer.
'olympian has dropped american underwear' is the wordplay.
'olympian' becomes 'zeus' (Greek god who lived on Mount Olympus).
'has dropped' is a deletion indicator.
'american' becomes 'US' (abbreviation for United States).
'underwear' becomes 'bras'.
'zeus' with 'us' taken out is 'ze'.
'ze'+'bras'='ZEBRAS'
Can you help me to learn more?
(Other definitions for zebras that I've seen before include "Striped horse-like animals" , "Black and white African animals" , "African striped animals" , "Black-and-white striped African equines" , "Striped mammals" .)