*Sinusitis doc (4)
'sinusitis doc' is the definition.
(I've seen this in another clue)
This is the entire clue.
(Other definitions for ent that I've seen before include "Tolkien's Treebeard, for one" , "Tolkien tree-man" .)
(Other definitions for lent that I've seen before include "Period of fasting" , "Gave for a limited period" , "Christian penitential season" , "Period from Ash Wednesday to Easter" , "days before Easter" .)