Outline of potential reason one’s on a trip still (6)
I believe the answer is:
placid
'trip still' is the definition.
'placid' can be an answer for 'still' (I've seen this before). I am not certain of the 'trip' bit.
'outline of potential reason one's on a' is the wordplay.
'outline of' says to hollow out the word (remove centre letters) (outline refers to the letters on the edges).
'reason one' becomes 'cid' (I can't explain this - if you can you should believe this answer much more).
'on' is a charade indicator (letters next to each other).
'potential' with its middle removed is 'pl'.
'cid' put after 'a' is 'acid'.
'pl'+'acid'='PLACID'
Can you help me to learn more?
(Other definitions for placid that I've seen before include "not easily angered" , "Cool and unruffled" , "Peaceable and not easily disturbed" , "Undisturbed" , "Calm and free from disturbance" .)