What is "to stick up for"

Stick \Stick\, v. i.

1. To adhere; as, glue sticks to the fingers; paste sticks to the wall.

   The green caterpillar breedeth in the inward parts of roses not blown, where the dew sticketh.
   --Bacon.

2. To remain where placed; to be fixed; to hold fast to any position so as to be moved with difficulty; to cling; to abide; to cleave; to be united closely.

   A friend that sticketh closer than a brother.
   --Prov. xviii. 24.

   I am a kind of bur; I shall stick.
   --Shak.

   If on your fame our sex a bolt has thrown, 'T will ever stick through malice of your own.
   --Young.

3. To be prevented from going farther; to stop by reason of some obstacle; to be stayed.

   I had most need of blessing, and ``Amen'' Stuck in my throat.
   --Shak.

   The trembling weapon passed Through nine bull hides, . . . and stuck within the last.
   --Dryden.

4. To be embarrassed or puzzled; to hesitate; to be deterred, as by scruples; to scruple; -- often with at.

   They will stick long at part of a demonstration for want of perceiving the connection of two ideas.
   --Locke.

   Some stick not to say, that the parson and attorney forged a will.
   --Arbuthnot.

5. To cause difficulties, scruples, or hesitation. This is the difficulty that sticks with the most reasonable. --Swift. To stick by.

   1. To adhere closely to; to be firm in supporting. ``We are your only friends; stick by us, and we will stick by you.''
      --Davenant.

   2. To be troublesome by adhering. ``I am satisfied to trifle away my time, rather than let it stick by me.'' --Pope. To stick out.

      1. To project; to be prominent. ``His bones that were not seen stick out.''
         --Job xxxiii. 21.

      2. To persevere in a purpose; to hold out; as, the garrison stuck out until relieved. [Colloq.]

         To stick to, to be persevering in holding to; as, to stick to a party or cause. ``The advantage will be on our side if we stick to its essentials.''
         --Addison.

         To stick up, to stand erect; as, his hair sticks up.

         To stick up for, to assert and defend; as, to stick up for one's rights or for a friend. [Colloq.]

         To stick upon, to dwell upon; not to forsake. ``If the matter be knotty, the mind must stop and buckle to it, and stick upon it with labor and thought.''
         --Locke.