vers

con- (thoroughly) + vert (turn) = turn something completely over into a new state. The word spans the physical (convert a garage into an office), the abstract (convert dollars to euros), and the spiritual (convert to a new faith — the original religious sense, where a person 'turns wholly' toward a new belief). Note the stress shift: to con-VERT (verb) vs a CON-vert (noun, a person who has changed faith).

di- (apart) + vers (turned) = 'turned in different directions.' Things that have each turned their own way end up varied and different — hence diverse. The same image powers the whole sub-family: divert (turn a path apart), diversity (the state of many-turning), diversify (to make turn apart). The hidden logic: difference is just many things facing different ways.

re- (back) + vers (turn) = turn back, turn around. Reverse covers turning a vehicle's motion backward (put it in reverse), flipping the order of things (reverse the list), and overturning a decision (the court reversed the ruling). It also names the back side of a coin or page. The thread is always a 180-degree turn of whatever direction was set.

contro- (against, opposite) + vers (turn) = two sides turned to face each other in opposition. A controversy is a dispute where people have squared off — literally 'turned against' one another. It's one of the family's clearest pictures: you can see the opponents pivoting to confront each other across an issue.

ad- (toward) + vert (turn) = turn attention toward. An advertisement is something built to swing your gaze toward a product. Strikingly, the same ad- + vert that means 'turn toward' (notice) also produced the hostile branch — adverse, adversary, adversity — where someone 'turns against' you. Same prefix, same root, opposite emotional charge, decided entirely by context.