It's more than obvious it shows grievance (6)
I believe the answer is:
plaint
'grievance' is the definition.
(I've seen this in another clue)
'it's more than obvious' is the wordplay.
'it' becomes ''t' (abbreviation. e.g. in 'tis).
'more than' says to put letters next to each other.
'obvious' becomes 'plain' (similar in meaning).
't' after 'plain' is 'PLAINT'.
'it shows' is the link.
This may not be right. Some or all of it may be part of another bit of the clue.
Can you help me to learn more?
(Other definitions for plaint that I've seen before include "Lamentation or grievance" , "Legal suit" , "Lamentation (poetic)" , "Accusation (law)" , "Accusation; charge" .)