Thus a ruler gets very wet (7)
I believe the answer is:
soaking
'very wet' is the definition.
(I know that soaking is a more specific form of the attribute very wet)
'thus a ruler' is the wordplay.
'thus' becomes 'so' (synonyms).
'ruler' becomes 'king' (king is a kind of ruler).
'so'+'a'+'king'='SOAKING'
'gets' acts as a link.
(Other definitions for soaking that I've seen before include "Wet" , "Drenched" .)