No it isn't
If you tackle in flag football it is a penalty.
There is no legal tackle in Gaelic football. The closest to one is that you can hit another player shoulder to shoulder. As to how to foul, there are all sorts of things that constitute fouls, like pushing a player, tripping him, pulling him, pulling his jersey, punching him and so on.
It is illegal to attempt to tackle a ballcarrier by grabbing any part of the helmet. Prior to 2008, an unintentional or "incidental" grab was a 5 yard penalty, and an intentional grab with twisting or pulling was a personal foul 15 yard penalty. As of 2008, all helmet grabs are penalized 15 yards. This penalty is called a facemask.
In flag football one pulls off the player with the ball's flag to tackle them. In tackle one physically tackles them.
If you tackle them with your arm, yes. Shoulder no. If you tackle the arm it is known as a clothesline. It is a type of tackle made infamous by Dick "Night Train" Lane. Many players were injured using this type of tackle. A majority of the time, if the hit is deemed vicious, it will be flagged for unnecessary roughness. If the tackle happens in the back of the neck and drags the player down (outside the tackle box), this is considered a horse-collar tackle, and it also a penalty.
There is no defined tackle in Gaelic Football. The closest thing to one is what is called a "shoulder". A player can hit a player shoulder to shoulder.
Pass, rush, yards, interception, fumble, penalty, tackle, helmet, touchdown
A Spear in football is when a player deliberately targets another player with the crown of their head when making a tackle.
The football player had to tackle the receiver so they wouldn't make a touchdown!!
The offending player would most likely get a straight red, and a penalty would be awarded.
The player who tackles the player with the ball will be credited. If 2 people tackle the player with the ball at the same time they will each be credited with 1/2 a tackle.