Woodworm is a tedious type (5)
I believe the answer is:
borer
'woodworm' is the definition.
The answer and definition can be both animals as well as being singular nouns.
Maybe they are linked in a way I don't understand?
'a tedious type' is the wordplay.
I cannot quite see how this works, but
'tedious type' could be 'bore' (I've seen this in another clue) and 'bore' is present in the answer.
A single letter 'r' remains which might be clued in a way I don't see.
This may be the basis of the clue (or it may be nonsense).
'is' acts as a link.
Can you help me to learn more?
(Other definitions for borer that I've seen before include "Drill" , "Tunnelling worm or insect" , "creature entering wood" , "Uninteresting type of" , "Hole-making worm or insect" .)