Verb
think straight (third-person singular simple present thinks straight, present participle thinking straight, simple past and past participle thought straight)
(usually in negative) To think clearly
It seems to me that a man who can think straight along for forty-seven years without changing a single idea ought to be kept in a cabinet as a curiosity. Jean Webster
Well, love is insanity. The ancient Greeks knew that. It is the taking over of a rational and lucid mind by delusion and self-destruction. You lose yourself, you have no power over yourself, you can't even think straight. Marilyn French
Now I'm starting, relatively, to think straight again. I live one day at a time, one hour at a time. What makes it all worthwhile is my children. Paula Yates
This left me alone to solve the coffee problem - a sort of catch-22, as in order to think straight I need caffeine, and in order to make that happen I need to think straight. David Sedaris