Being not at all steady, let the horse out? (8)
I believe the answer is:
unstable
'being not at all steady let the horse out?' is the definition.
I can't tell whether this definition defines the answer.
'being not at all steady' is the wordplay.
'being not' becomes 'un' (prefix meaning 'not').
'at' says to put letters next to each other.
'all steady' becomes 'stable' (associated in meaning. I am not sure about the 'all' bit.).
'un'+'stable'='UNSTABLE'
Can you help me to learn more?
(Other definitions for unstable that I've seen before include "Subject to change, variable" , "not reliable" , "Not steady, volatile" , "lacking security" , "Not well-balanced, liable to wobble" .)