Rengar's 'Leap'

What do you mean "avoid taking damage"?

Most non-blink movement abilities don't prevent the champion from taking damage. The only exceptions I can think of make the champion untargetable.

There is no difference between leaps and dashes in this game; it doesn't calculate a vertical axis.

Guess you never seen Tristana getting snapped by Caitlyn traps whilst mid-air, eh?

Gnar doesn't avoid damage. They're's basically no difference between a leap and a dash.

If the Champion physically travels the distance - Dash

If the Champion "appears" at the destination without moving in between - Blink.

His "leap" is considered a dash in mechanical terms. It is just thematically called a leap. see also: Zac, Trist, Kha'Zix. All of them can still be hit/take damage mid-dash. There is no such thing as "leaping over" a trap or spell unless the dash specifically makes them untargetable or invulnerable during that portion.

Remember that the game appears to have a Z-axis in terms of visuals, but it doesn't exist in terms of gameplay. It can get frustrating when it shows.