I don’t know why every person who’s addressing a smurf is addressing “throwing”. There’s no way to catch someone who wants to soft throw, somebody could get 200 healing per minute on purpose just to throw and you’ll never catch, it’s impossible since there’s no public stats in game to correlate with the rank you’re at. (“Throwing” doesn’t address the problem of “Smurfs”)
A smurf is a player who is a higher rank player than what they claim on the (lower rank account) to deceive the game to put them in lower ranked matches to dominate the lower ranks.
If you see a level 26, with a overwatch logo default profile picture, playing well above your rank (you naturally know how good the average DPS are in your rank), then he’s a smurf… a blatant one, purposely there just to ruin the competitive match.