The most common and most likely answer to this crossword clue is the 3 letter word TIP
I've seen this crossword clue in Financial Times
T
I
P
More clues leading to the result TIP
- Hint that’s a lot of rubbish?
- Suggestion: mine is taken up
- Force trained up, expending energy for new form of attack
- Provide clue for little reward
- Advice of mine sent back
- Point?
- Load of rubbish in hole mounting up
- Hint given by superior gent, carrying minimal cash
- Advice: where to put rubbish?
- Dump mine on the way up
Buddy explains!

The straight part
We know that "Dump" is the straight/definition part of the clue. The straight part is often a synonym or definition, in this case dump = tip.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 TIP mean?
TIP noun- The tip of the external ear.
- A small earpiece or earplug.
- The part of an earbud that contours to the ear canal.
- The removal of the tip of a cat's ear, done to indicate that the cat has been fixed.
- The extreme end of something, especially when pointed; e.g. the sharp end of a pencil.
- A piece of metal, fabric or other material used to cover the top of something for protection, utility or decoration.
- The end of a bow of a stringed instrument that is not held.
- (chiefly in the plural) A small piece of meat.
- A piece of stiffened lining pasted on the inside of a hat crown.
- A thin, boarded brush made of camel's hair, used by gilders in lifting gold leaf.
- To provide with a tip; to cover the tip of.
- (skittles) The knocking over of a skittle.
- An act of tipping up or tilting.
- An area or a place for dumping something, such as rubbish or refuse, as from a mine; a heap (see tipple); a dump.
- Rubbish thrown from a quarry.
- (by extension) A recycling centre.
- A very untidy place.
- The act of deflecting with one's fingers, especially the fingertips
- A tram for expeditiously transferring coal.
- (To cause) to become knocked over, fall down or overturn.
- (To cause) to be, or come to be, in a tilted or sloping position; (to cause) to become unbalanced.
- To drink.
- To dump (refuse).
- To pour a libation or a liquid from a container, particularly from a forty of malt liquor.
- To deflect with one′s fingers, especially one′s fingertips.
- A light blow or tap.
- To hit quickly and lightly; to tap.
- A gratuity; a small amount of money left for a bartender, waiter, taxi driver or other servant as a token of appreciation.
- To give a small gratuity to, especially to an employee of someone who provides a service.
- To give, pass.
- A piece of private or secret information, especially imparted by someone with expert knowledge about sporting odds, business performance etc.
- A piece of advice.
- To give a piece of private information to; to inform (someone) of a clue, secret knowledge, etc.
- A kick or phase; one's current habits or behaviour.
- A particular arena or sphere of interest; a front.