"That hound won't hunt." -- Of an ill-conceived plan or scheme, a mild insult.
"Counting Coin." -- Thieves cant expression meaning to size up or case a
particular potential victim, particularly for a cut-purse job.
"To sell slaves in Silverymoon." -- To do something that violates local
law/custom in a particularly outrageous and obvious way and then say:"I didn't
know any better."
"When the walls fall down." -- In Waterdeep, to mean "When Hell freezes over."
"To miss the tide." -- In Waterdeep, to miss out on a wonderful opportunity
because of bad planning.
"Between the Dragon and the Desert." -- As in "Between the Devil and the Deep"
to be caught between two equally unattractive possibilities.
"Fool's Gold" or "To take Fool's Gold." -- An adventurer's
watchword meaning to take on an adventure so dangerous that only the god Torm
(The True, the Foolish) would attempt.