My brother asked me this question:
You can be disruptive, but can you be ruptive? For example, one can be
disrespectful and it is also possible to be respectful…
I thought ruptive would have to mean the opposite of disruptive (because…pattern?). I have looked up the definition of ruptive and it seems that both ruptive and disruptive have the same meaning. Why is this so and why is there a distinction if they both mean the same thing?
Upon further investigation eruptive and irruptive are also in the same boat. Again why? Is this a common pattern? Examples?
Best Answer
Your premise of equivalence is faulty for both of the word pairs you present. The 1913 Webster's definition for the obsolete term ruption that your link points to states "A breaking or bursting open; breach; rupture".
This is not the same as the definition of disruption, which Oxforddictionaries.com (ODO) defines as "Disturbance or problems that interrupt an event, activity, or process".
Similarly, ODO defines eruptive as "Of, relating to, or formed by volcanic activity," and irruptive as an adjective derived from the noun irrupt, which means "[To] enter forcibly or suddenly".