Dipterous insect and Insect

Dipterous insect noun - Insects having usually a single pair of functional wings (anterior pair) with the posterior pair reduced to small knobbed structures and mouth parts adapted for sucking or lapping or piercing.

Insect and dipterous insect are semantically related. In some cases you can use "Insect" instead a noun phrase "Dipterous insect".

Insect noun - A person of no importance or influence.

Dipterous insect and insect are semantically related. Sometimes you can replace phrase "Dipterous insect" with "Insect", this terms are similar.