I grew annoyed about a little pest (6)
I believe the answer is:
earwig
'little pest' is the definition.
Although both the answer and definition are singular nouns, I can't understand how they can define each other.
'i grew annoyed about a' is the wordplay.
'annoyed' indicates anagramming the letters.
'about' is an insertion indicator.
'i'+'grew'='igrew'
'igrew' anagrammed gives 'erwig'.
'erwig' going around 'a' is 'EARWIG'.
Can you help me to learn more?
(Other definitions for earwig that I've seen before include "listen in?" , "Eavesdrop (informal)" , "flatterer" , "An insect, I wager (anag.)" , "Small insect with pincers at end of its body" .)