Semi Bluff

A semi bluff is a situation where you don't have a strong hand at the moment, but you have a good draw to a strong hand and may also win the pot by betting or raising.

For example, your opponent has been betting on each round and on 5th street shows the following hand:

Back of Card Back of Card King of Clubs Two of Hearts Ten of Hearts    
Hole Cards Up Card 4th Street 5th Street 6th Street River

You have:

King of Hearts Ace of Clubs Three of Clubs Jack of Clubs Ten of Clubs    
Hole Cards Up Card 4th Street 5th Street 6th Street River

By raising on 5th street you give yourself two ways to win: you can either get him to lay down his hand now, or you can complete your flush or straight draw to win the hand even if he does call. You may also gain a free card on 6th street if he checks and you have missed your draws.