The most common and most likely answer to this crossword clue is the 6 letter word SEESAW
I've seen this crossword clue in The Sunday Telegraph
S
E
E
S
A
W
More clues leading to the result SEESAW
- Playground amenity was set up by diocese
- Match was recalled as an up-and-down affair
- Spot used to be put back for playground attraction
- Understand wise words and oscillate
- Something for children to observe, now and then
- Notice present then past feature in playground
- Notice saying ‘Go Up and Down‘
- Observes endless wonder in children’s plaything
- Deep wound reported as plank sat upon
- Notices a wife go from one extreme to the other
Buddy explains!

The straight part
We know that "go up and down" is the straight/definition part of the clue. The straight part is often a synonym or definition, in this case go up and down = seesaw.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 SEESAW mean?
SEESAW noun- A structure composed of a plank, balanced in the middle, used as a game in which one person goes up as the other goes down.
- A series of up-and-down movements.
- A series of alternating movements or feelings.
- To use a seesaw.
- (by extension) To fluctuate.
- To cause to move backward and forward in seesaw fashion.
- Fluctuating.