To keep to oneself, to be secretive, to be very cautious in one's dealing with people and giving nothing much or nothing at all away. (As if one were playing cards and not permitting anyone to see any of the cards.)
"He is very cautious. He plays his cards close to his chest."
"You seem to be playing your cards close to your vest."
In sales terms, a whale is a prospect that is significantly larger than an organization’s average customer.
Whales are large and extremely difficult to close. Due to their immense size, they are highly sought-after.
A whale is typically identified at first by a whale hunter on the sales team, but often requires cross-discipline participation in order to close; this includes assistance from operations, engineering, creative, client success, and business development teams.
"Shit...the sales director chewed me out on the sales call this morning. He's totally pissed that I have nothing in my pipeline. I've been focused on this one whale for so long that I haven't had time to prospect for normal-sized deals."
Dr. Drew on Celebrity Rehab said "All of a sudden what had been just another Hollywood proposal became for him an unexpected blessing, an opportunity for growth. In drug recovery language, that's called a "God shot."