The most common and most likely answer to this crossword clue is the 9 letter word STIPULATE
I've seen this crossword clue in The Times
S
T
I
P
U
L
A
T
E
More clues leading to the result STIPULATE
- Fan replacing marks with pence to lay down?
- Insist on fan keeping quiet for minutes
- Insist on ordering it, plus tea
- Guarantee from uranium mines in recession recently
- Lay down tulips, frantically worried
- Specify page should wear tailored teal suit
- Lay down rubbish, burying uranium at bottom of dump
- ‘Lay Down Sally’ initially done in end, overdue
- Demand one jerk doesn’t end in government
Buddy explains!

The straight part
We know that "to lay down" is the straight/definition part of the clue. The straight part is often a synonym or definition, in this case to lay down = stipulate.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 STIPULATE mean?
STIPULATE verb- To require (something) as a condition of a contract or agreement.
- To specify, promise or guarantee something in an agreement.
- To acknowledge the truth of; not to challenge. E.g. "The defense stipulates that the witness has identified my client."
- Having stipules; that is, having outgrowths borne on either side of the base of the leafstalk.