Go quickly out of control, indication of indecision after caution (6)
I believe the answer is:
career
'go quickly out of control' is the definition.
'career' can be an answer for 'go' (careering is a kind of going). I am unsure of the 'quickly out of control' bit.
'indication of indecision after caution' is the wordplay.
'indication of indecision' becomes 'er' (I can't justify this - if you can you should believe this answer much more).
'after' means one lot of letters go next to another.
'caution' becomes 'care' (synonyms).
'er' put after 'care' is 'CAREER'.
Can you help me to learn more?
(Other definitions for career that I've seen before include "Rush headlong" , "Go at top speed through a working life?" , "Run headlong at high speed" , "Tear" , "Vocation; rush" .)