Thanks Tsuwm - doncha just hate those "obsc" etymologies!!

Am struggling with the derivation from the Hindi though. Having lived in Bombay/Mumbai, "Thik hai" was absorbed into the stales' family dialect years ago. We pronounce it "tee - khi" which is nothing like "tick-ett-ee". And whence the "boo"?

Like the idea of it being service slang.

stales