Bluff
A bluff is a bet or raise made with a hand that is unlikely to win at a showdown, so all of its profit comes from the chance the opponent folds.
That is the whole test. If a hand can win by being shown down, betting it is a value bet or a thin value bet, not a bluff. If it can only win by making someone fold, it is a bluff, and the question becomes how often that has to work to pay for itself.
The arithmetic is the same as pot odds, seen from the other side. A bet of half the pot risks 0.5 to win 1, so it needs a fold roughly one time in three to break even, before counting the times you are called and still win.
an example
your cards
board
You missed everything: no pair, no straight, no flush. Checked to on the river, this hand wins nothing at a showdown. It can still win the pot, but only if a bet makes a better hand fold, and that is the only reason to put another chip in.
This example is made up. The real one is in your own hand history: find bluff in your own hands and see how often it came up and what it cost you.
related terms
Semi-bluff
A semi-bluff is a bet or raise with a hand that is probably not the best right now but can still improve, so it can win ...
Fold equity
Fold equity is the part of a bet or raise that earns its money from the chance the opponent folds, rather than from the ...
Range
A range is the whole set of hands a player could hold in a given situation, rather than a guess at the one hand they act ...
next
Knowing the word is not the same as seeing it.
Forty hands against a bot, no account, and your own hand history at the end.