The most common and most likely answer to this crossword clue is the 4 letter word CART
I've seen this crossword clue in The Daily Telegraph
C
A
R
T
More clues leading to the result CART
- Haywain, say, seen in the foremost of Constable’s paintings?
- Vehicle requiring constant skill
- Vehicle trapped by one tramcar after another
- Barrow by rail, shortly to return
- 10‘s about right
- No thoroughbred in unusually short race
- Truck‘s detailed route going north
- Carer host spoilt, one of a lumbering nature?
- Vehicle taking rough road north stopping prematurely
- Rex Hammerman seen in action; he’s good at draughts!
Buddy explains!

The straight part
We know that "one of a lumbering nature" is the straight/definition part of the clue. The straight part is often a synonym or definition, in this case one of a lumbering nature = cart.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 CART mean?
CART noun- A small, open, wheeled vehicle, drawn or pushed by a person or animal, more often used for transporting goods than passengers.
- A small motor vehicle resembling a car; a go-cart.
- A shopping cart.
- To carry goods.
- To carry or convey in a cart.
- To remove, especially involuntarily or for disposal.
- To expose in a cart by way of punishment.
- A tape cartridge used for pre-recorded material such as jingles and advertisements.
- A cartridge for a video game system.