The most common and most likely answer to this crossword clue is the 8 letter word SCORPION
I've seen this crossword clue in The Guardian
S
C
O
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N
More clues leading to the result SCORPION
- Venomous creature seen in house, located by noon
- Arachnid is on crop unfortunately
- Arachnid found in house at noon
- Insect offspring devouring core of rising taproot
- Tail of this one concerning, going over back of body
- Expert retrospective probes descendant, one born on Hallowe’en
- Shoot capturing soldiers parking tank?
- Sign name for an arachnid
- Descendant admits returning for stinger
- Sign NCO produced in Swiss town
Buddy explains!

The straight part
We know that "Insect" is the straight/definition part of the clue. The straight part is often a synonym or definition, in this case insect = scorpion.The cryptic/wordplay part
In cryptic crossword there's often an wordplay/cryptic part as well.This part involves a more complex hint, such as an anagram, homophone, hidden word, etc.
Sadly, We don't have an explanation for this specific crossword clue yet.
What does SCORPION mean?
SCORPION noun- Any of various arachnids of the order Scorpiones, related to the spiders, characterised by two large front pincers and a curved tail with a venomous sting in the end.
- An ancient military engine for hurling stones and other missiles.
- A very spiteful or vindictive person.
- A cheerleading move in which one foot is pulled back and held up with both hands while the performer stands on the other foot.
- A whip with points like a scorpion's tail.