The most common and most likely answer to this crossword clue is the 7 letter word TROUSER
I've seen this crossword clue in The Sunday Telegraph
T
R
O
U
S
E
R
More clues leading to the result TROUSER
- Lift in holiday centre going the wrong way, uncle's head stuck in it
- Pocket in short pants
- Some disastrous error is appropriate
- Pocket of resistance on banks of Tiber river
- Appropriate climbing haunt, round heart of Hindu Kush
- Pocket for everyone in Eastbourne, say, in retirement
- Appropriate clothing a little short
- Take short run with addict
- Something stirring by cheat’s right pocket
- Starting to rely on employer’s pocket
Buddy explains!
The straight part
We know that "Device that decreases" is the straight/definition part of the clue. The straight part is often a synonym or definition, in this case device that decreases = trouser.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 TROUSER mean?
TROUSER noun- (used attributively as a modifier) Of or relating to trousers.
- (in clothing retail and fashion) A pair of trousers.
- To put money into one's trouser pocket; to pocket.
- To legally remove funds from an organization for personal use.
- To secretively steal an item or money for personal use.