And don't we have a right over our own bodies? If somebody wants to end their life, who are you to deny them this?
No we don't own our own bodies. How could we when we had no choice in our own creation? We are merely caretakers. Our bodies belong to the One who created them.
The only reason we do/should try to prevent suicides is because often suicidal people are not thinking straight, are under undue stress, or are suffering from mental problems. Help clear those up and then if they still want to end their life, they shouldn't be scoffed at or judged by you.
Mind your own business. Live and Let Die
*enter James Bond*
How can you say we should help suicidal people then end it with live and let die if they still want to do it? How helpful is that? You can't be sure they need more help than you offered but you gave up believing that at the end it's their right to die? Surely it'd be better if you helped them until they didn't want to die - or you didn't try in the first place. Like you said they are not thinking right.
As far as the original question goes, regardless of definition, both acts (murder & suicide) end in taking a life - therefore both are a big sin. But God willing, given the nature of suicide, it's punishment maybe of a lesser degree than taking life by murder which can be premediated and done out of a sound mind.
Another thing comes to mind - about owning our own bodies. Now think.. if a person destroys
his property by setting fire to it, he will be charged/punished for arson. Yet, he can salvage the damage because it belongs to him and he has full rights over his property.
But when it comes to life, we don't have that right. We can't bring a suicider back to life to punish him and nor can he fix himself up again. Then what rights do we have over something we are powerless to sustain/fix? If God wanted, He could've given us the ability to bring ourselves or that person back to life and punish them. But He didn't. By limiting our capabilities Allah has proven that life belongs to Him. Unlike worldly property, which we can claim 100% rights over, we can't claim to have rights to our own life when we have no power to sustain it. It simply doesn't make sense.