Meanings

refractory

obtaining agreement by consultation

flame reaction

neutralization reaction

acid-base reaction

overfitting

applied economics

extremely powerful weapon (e.g. nuclear)

return fire

too busy to deal with

fission chain reaction

qualification requirement (for a job)

incredible response (company dealing with a complaint, celebrity dealing with fans, etc.)

whether one likes it or not

willy-nilly

induced reaction

cheerleading competition

person unfit for society

to be up-to-date

side effect (of a vaccine)