excogitate in WordNet English dictionary

1. reflect deeply on a subject
   "I mulled over the events of the afternoon"; "philosophers have speculated on the question of God for thousands of years"; "The scientist must stop to observe and start to excogitate"
   chew over  think over  meditate  ponder  excogitate  contemplate  muse  reflect  mull  mull over  ruminate  speculate 
   
2. come up with (an idea, plan, explanation, theory, or principle) after a mental effort
   "excogitate a way to measure the speed of light"
   invent  contrive  devise  excogitate  formulate  forge