Whirlpool – cyclist Merckx (4)
I believe the answer is:
eddy
I believe this is a double definition.
'whirlpool' is the first definition.
(an eddy is a small whirlpool)
'cyclist merckx' is the second definition.
(I've seen this in another clue)
(Other definitions for eddy that I've seen before include "Whirling current" , "movement going round in circles" , "Little swirl in water" , "She founded Christian Science in 1866, d. 1910" , "Swirl; small whirlpool" .)