The most common and most likely answer to this crossword clue is the 3 letter word MAT
I've seen this crossword clue in The Times
M
A
T
More clues leading to the result MAT
- What martial arts trainer needs for beginners?
- Companion shortened floor covering
- Finalists in ballroom drama cut a rug
- Dull, impact oddly lacking
- Dull piece of fabric we may wipe our feet on?
- Get into a tangle, missing umlauts frequently
- Complicated mass is dull
- Where a cat, or a mouse, might sit
- Friend’s lost key found by door
- Dull floor covering
Buddy explains!

The straight part
We know that "What martial arts trainer needs for beginners?" is the straight/definition part of the clue. The straight part is often a synonym or definition, in this case what martial arts trainer needs for beginners? = mat.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 MAT mean?
MAT noun- A flat piece of coarse material used for wiping one’s feet, or as a decorative or protective floor covering.
- A small flat piece of material used to protect a surface from anything hot or rough; a coaster.
- A floor pad to protect athletes.
- A thickly tangled mess.
- A thin layer of woven, non-woven, or knitted fiber that serves as reinforcement to a material.
- A thin surface layer; superficial cover.
- To cover, protect or decorate with mats.
- To form a thick, tangled mess; to interweave into, or like, a mat; to entangle.
- (coppersmithing) An alloy of copper, tin, iron, etc.; white metal.
- A showing of a movie, sporting event, or theatrical performance in the morning or afternoon.
- A woman's dress to be worn in the morning or before dinner.
- A material or component needed for a crafting recipe.
- A decorative border around a picture used to inset and center the contents of a frame.
- A background, often painted or created with computers
- (pyrometallurgy) The molten metal sulfide phases typically formed during smelting of copper, nickel, and other base metals.