1. [n]  small air-breathing arthropod
2. [n]  has a nasty or unethical character undeserving of respect

Insect
Explores the anatomy, behavior, and ecological role of the world's most populous class of animals.

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1. \In"sect\, n. [F. insecte, L. insectum, fr. insectus, p.
   p. of insecare to cut in. See {Section}. The name was
   originally given to certain small animals, whose bodies
   appear cut in, or almost divided. Cf. {Entomology}.]
   1. (Zo["o]l.) One of the Insecta; esp., one of the Hexapoda.
      See {Insecta}.
   Note: The hexapod insects pass through three stages during
         their growth, viz., the larva, pupa, and imago or
         adult, but in some of the orders the larva differs
         little from the imago, except in lacking wings, and the
         active pupa is very much like the larva, except in
         having rudiments of wings. In the higher orders, the
         larva is usually a grub, maggot, or caterpillar,
         totally unlike the adult, while the pupa is very
         different from both larva and imago and is inactive,
         taking no food.
   2. (Zo["o]l.) Any air-breathing arthropod, as a spider or
      scorpion.
   3. (Zo["o]l.) Any small crustacean. In a wider sense, the
      word is often loosely applied to various small
      invertebrates.
   4. Fig.: Any small, trivial, or contemptible person or thing.
      --Thomson.
   {Insect powder},a powder used for the extermination of
      insects; esp., the powdered flowers of certain species of
      {Pyrethrum}, a genus now merged in {Chrysanthemum}. Called
      also {Persian powder}.
   

2. \In"sect\, a.
   1. Of or pertaining to an insect or insects.
   2. Like an insect; small; mean; ephemeral.