technique - How do you tell a character's backstory without explicitly telling it?

I want to tell a character's backstory, but I don't want that character to tell it directly to the protagonist, or to use another character to do it for them. Is there a way to do this?

Answer

In addition to the advice of weaving it in, in pieces, I'd suggest trying to add it not through exposition, not even exposition in dialog, but rather through action and then an offhand not-quite-exposing remark.

Example: Backstory - Trixie had been trained as a ninja, a secret weapon for the other side, she was their ultimate assassin.

But we don't know that. We just know that:

Trixie is a seemingly sweet twenty-something. She's tagging along with Pancho for reasons we don't know. He's on a mission to save the resistance. He's the guy with all the amazing power. They get in a scrap with a bad guy, who throws a knife at Pancho, but Trixie catches the knife mid-air. (Bad guy runs off.)

Pancho says, "Whoa. How did you do that?"

"You'll find I'm full of surprises," Trixie replied.

^ No exposition, except the amazing ability to catch the knife mid-air (which is shown.). But now Pancho wants to know (that's some tension.) Of course the reader does too.

Pancho starts to nag her, but she won't tell him (tension).

Eventually, other hints come out, through a variety of incidents, and there's some sort of nice reveal chapters later. Dribbling out the backstory gives the reader the sense of progress in addition to the other plot points that are progressing.

This backstory should be integral to the plot, but I assume you have that covered.