Delicate flower Justin Bieber was accused of punching his former bodyguard, who served in the Israeli military.

While Biebs may be slow enough to forget to check for cameras before lighting up, there's no way he's that dumb -- and sources close to him agree.

Moshe Benabou, who protected Bieber from rabid fans and possible serial killers from March 2011 to October 2012 is suing the singer.

Benabou claims that Bieber punched him in the chest numerous times during a particularly heated incident in which they disagreed about how to deal with a member of the Biebs' entourage.

Apparently, this incident, combined with unpaid overtime, is enough for a $420,000 suit.

Bieber's camp, naturally, denies anything untoward went down.

"This whole thing is baseless and meritless," a source, sounding suspiciously like a publicist or lawyer, told Us Weekly. "Justin never hit him and couldn't! He is so much smaller. This whole thing is a lie."

Further, TMZ discovered that Benabou was fired after it was revealed he was quite a bit of a liar. For example: He said he worked for Justin Timberlake before being hired by the 'Believe' singer's camp ... which was patently false.

Still, it's a headache Bieber doesn't really need right now. After another split with Selena Gomez and the release of possible pot photos, we bet he could use something to get the edge off.

Oh, wait.