"preparar en secreto" in English

to prepare- to ready- to make up- to brew- to build- to cast- to concoct- to condition- to cook- to do- to do- to draft- to dress- to equip- to fix- to gear up- to get- to groom- to lay- to lay out- to make- to mix- to mix up- to mount- to plot out- to prime- to prime- to put together- to rustle up- to train- to coach- to add up- to dispense- to get … ready- to tutor

Jan

at- in- into- on- on- on- on- with- as- by

secrecy- secret- furtiveness- sounding board

secret- backdoor- undercover- classified- hole-and-corner- sneaking- top secret- undeclared

to secrete