A word game - Enforcer

[Weezy]

When I was a child (and dinosaurs still ruled the Earth) we use to play a modified version of Scrabble we called Enforcer - so called because the object of the game was to force the next player to complete a word...

1). The word cannot be a proper noun (Capitalised like a town/city name, a person's name, etc )...
2). The word must be at least 5 letters long and any smaller words within it are disregarded (like the in therapy)
3). Any added letter can be challenged...If the provider cannot provide a valid word that contains those letters in that exact order he loses and is barred from providing any new letters for that word...For example: if the letters are STRENGT and a player adds "v" he is eliminated for the remainder of that round...
4). If ANY player can prove there is already a valid word within the current working one (larger than 4 letters) then he/she wins and gets to start the next one...

The winner is the person that provided the final letter before completing the word and he/she gets to start the next word...

P.S. Texters will probably not do very well at this...
P.P.S. This is where all you spelling bee geeks get your revenge!

To get it going, I'll start with the letter:
R