Ability to Walk Steadily on the Deck of a Boat
Puzzle 6 of Brad Pitt Easy Pack
Question is: Ability to Walk Steadily on the Deck of a Boat
and the answer is: SEALEGS
Word Meaning:
SEA LEGS — (idiomatic, nautical) The ability, when walking aboard a ship, to anticipate the motion of the deck so as to walk steadily without losing balance.
Definitions from Wiktionary.