I miss step out - a hopeless case! (9)
I believe the answer is:
pessimist
'a hopeless case' is the definition.
The definition and answer can be both people as well as being singular nouns.
Perhaps you can see an association between them that I don't see?
'i miss step out' is the wordplay.
'out' indicates anagramming the letters (out can mean wrong or inaccurate).
'i'+'miss'+'step'='imissstep'
'imissstep' with letters rearranged gives 'PESSIMIST'.
Can you help me to learn more?
(Other definitions for pessimist that I've seen before include "The glass is always half-empty for this person" , "One expects the worst" , "One sees the glass as always being half-empty" , "Glass-half-empty person" , "Half-empty-glass person" .)