The most common and most likely answer to this crossword clue is the 7 letter word DEADPAN
I've seen this crossword clue in The Sunday Telegraph
D
E
A
D
P
A
N
More clues leading to the result DEADPAN
- Notice secretary’s put in study unable to be read?
- Unsmiling principal brings in commercial parking
- Unemotional father framing “Head of Egyptian God”
- Old man welcomes card player with poker face
- Gone to meet Maker — God giving little away
- Expressionless god unresponsive at first
- Expressionless bloody monster
- College fellow holding fragments of pad that’s hard to decipher
- Showing no emotion over divine corpse
- Boring rubbish showing no emotion
Buddy explains!

The straight part
We know that "dry" is the straight/definition part of the clue. The straight part is often a synonym or definition, in this case dry = deadpan.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 DEADPAN mean?
DEADPAN noun- A style of comedic delivery in which something humorous is said or done while not exhibiting a change in emotion or facial expression.
- To express (oneself) in an impassive or expressionless manner.
- Deliberately impassive or expressionless.
- Having such a face or look.
- Impassive.
- In a deadpan manner.