Some words just can’t be qualified, such as unique. Something either is or isn’t unique – that’s all there is to it. Here are a few more words of that type.
Crucial derives from the Latin crux, meaning cross. The word originally meant cross shaped, but took on the meaning of deciding between opposing arguments in the 19th century. From there it was a short stretch to its current meaning of decisive.
Vital derives from the Latin words vitalis and vita meaning life. Its meaning has changed through the centuries. In the 14th century it meant pertaining to life; in the 15th it meant essential to life or sustaining life; in the 16th it meant endowed with life. By the 17th it had come to mean life giving or essential to the existence of something, which is its meaning now.
Essential is presumed to be derived from the Latin esse – to be – via essence, which denotes that qualities that make a thing what it is.
It’s common to hear people talking about issues that are highly crucial, most essential and very vital, however these uses are wrong. Something is either crucial or essential or it isn’t – and nothing can be more vital than another thing which is vital.