The keyword is joy, with its variations of rejoice, and rejoicing.
"Quiet Talks on Service"
S. D. Gordon
Nevertheless, I think that with us the keyword is "inevitability," or, as I should be inclined to call it, "impenitence."
"Eugenics and Other Evils"
G. K. Chesterton
But with the -k or -apropos option, it expects the argument to be a keyword.
"Debian GNU/Linux: Guide to Installation and Usage"
John Goerzen and Ossama Othman