Rank obtained by Scottish island over time (6)
I believe the answer is:
arrant
'rank' is the definition.
(synonyms)
'scottish island over time' is the wordplay.
'scottish island' becomes 'arran' (Isle of Arran).
'over' means one lot of letters go next to another (in a down clue, some letters go over others).
'time' becomes 't' (abbreviation).
'arran'+'t'='ARRANT'
'obtained by' is the link.
(Other definitions for arrant that I've seen before include "Utter and absolute, maybe nonsense" , "Rat ran badly and became unmitigated" , "Downright - notorious" , "Extreme or flagrant, perhaps nonsense" , "'Complete, stark (6)'" .)