Irritant (4)
'irritant' is the definition.
(I've seen this in another clue)
This is the entire clue.
(Other definitions for pest that I've seen before include "Destructive insect or other animal" , "Troublesome person" , "Annoying creature" , "Disease with a high death rate" , "Destructive insect or nuisance" .)
'irritant' is the definition.
(I know that irritant can be written as thorn)
This is the entire clue.
(Other definitions for thorn that I've seen before include "Old Norse character" , "Spiny bush" , "Spine - prickle - Old English runic letter" , "Sharp point on a shrub" , "problematic point" .)