Motion diagram. A Deaf-recorded clip from the PopSign corpus (CC BY 4.0) exists for this sign and can be placed here.
DRY
“dry”
How to make it
Drag a hooked index finger ('X') across your chin from one side to the other.
Where the sign comes from
UnknownNo reliable source. We'd rather say so than invent one.
Wiping the mouth dry is the usual explanation; it is a reading, not a documented origin.
No sources — which is the point of the “unknown” tier. If you know of a documented account, the historical databases are where to check it.
The sign, taken apart
Every ASL sign is built from a handshape, a place it's made, and a movement. Learn to see these three and you can read and store any sign.
Location
Chin
Made at the chin.
Movement
a straight path
One-handed.
Palm facing down.