The reason for something is a fact or situation which explains why it happens or what causes it to happen.
Who would have a reason to want to kill her
If you say that you have
reason to believe something or to have a particular emotion, you mean that you have evidence for your belief or there is a definite cause of your feeling.
The ability that people have to think and to make sensible
judgements can be referred to as reason.
If you reason that something is true, you decide that it is true after thinking carefully about all the facts.
If you do not know why someone did something, you can say that they did it for reasons best
known to themselves. You usually use this expression when you do not agree with what they did.
n
If one thing happens by reason of another, it happens because of it. (FORMAL)
If you say that
something happened or was done for no reason, for no good reason, or for no reason at all, you mean that there was no obvious reason why it happened or was done.
The guards, he said, would punch them for no reason.
For no reason at all
all strange meaning of it already making sence ,hence,That
intellectual power or faculty (usually regarded as characteristic of mankind, but sometimes also attributed in a certain degree to the lower animals) which is ordinarily employed in adapting thought or action to some end; the guiding principle of the human mind in the process of thinking.