cog·i·tate 
/ˈkɑ:ʤəˌteɪt/ verb
cog·i·tates; cog·i·tat·ed; cog·i·tata·ting /ˈkɑ:ʤəˌteɪt/ verb [no obj] formal : to think carefully and seriously about something
▪ I was cogitating about/on my chances of failing.
▪ I was cogitating about/on my chances of failing.
— cog·i·ta·tion /ˌkɑ:ʤəˈteɪʃən/ noun
[noncount] ▪ a problem that requires further cogitation [=thought] [count] ▪ the cogitations of his mind
/ˌkɑ:ʤəˈteɪʃən/ noun [noncount] ▪ a problem that requires further cogitation [=thought] [count] ▪ the cogitations of his mind
