Remains a cert, somehow, close to success (6)
I believe the answer is:
traces
'remains' is the definition.
Although both the answer and definition are verbs in their -s form, I don't see how one could define the other.
'a cert somehow close to success' is the wordplay.
'somehow' is an anagram indicator.
'close to' suggests the final letters (the close of something is the end).
The final letter of 'success' is 's'.
'a'+'cert'='acert'
'acert' with letters rearranged gives 'trace'.
'trace'+'s'='TRACES'
Can you help me to learn more?
(Other definitions for traces that I've seen before include "Finds; hints" , "Finds; small quantities" , "Signs in crates" , "Vestiges (that may be kicked over?)" , "Slight indications on parts of the harness" .)