Sentimental and terribly wet, note (4)
I believe the answer is:
twee
'sentimental' is the definition.
(I've seen this before)
'terribly wet note' is the wordplay.
'terribly' is an anagram indicator.
'note' becomes 'e' (musical note).
'wet' anagrammed gives 'twe'.
'twe'+'e'='TWEE'
'and' is the link.
(Other definitions for twee that I've seen before include "Sentimental, quaint" , "Overly cute" , "Rather too pretty" , "Affectedly cute" , "Small and sweet (colloq.)" .)