From Longman Dictionary of Contemporary Englishthink straightthink straight[usually in negatives] to think clearly I’m so nervous I can’t think straight. How can I think straight with you talking all the time? → think
Examples from the Corpus
think straight• He was so dazed by all he had just been through that he couldn't think straight.• I - I can't think straight.• Since that day she had not been able to sleep, or to think straight.• The buzz made it hard to think straight.• Then she might - just might - be able to think straight.• Sooner or later he would be too exhausted to think straight and would give up the fight against himself.• You are horrified, you can not think straight, as you stare at the broken body.• One could never think straight when the body's ills took all one's attention. 