Hitler's disastrous slide (7)
I believe the answer is:
slither
'slide' is the definition.
('slither' can be a synonym of 'slide')
'hitler's disastrous' is the wordplay.
'disastrous' is an anagram indicator.
'hitlers' with letters rearranged gives 'SLITHER'.
(Other definitions for slither that I've seen before include "Snake along" , "Slide on slippery surface" , "Slide, slip" , "Undulate" , "Move smoothly over a surface with a twisting motion" .)