1. In an exhaustive manner
   "we searched the files thoroughly"
   - exhaustively 
2. Completely and absolutely ('good' is sometimes used informally for 'thoroughly')
   - soundly, good

See also: thorough

• cosmography
• cosmolatry
• cosmologic
• cosmological
• cosmological constant
• cosmological principle
• cosmologist
• cosmology
• cosmonaut
• cosmopolitan
• cosmopolitanism
• cosmopolite
• cosmos
• cosmotron
• cosponsor
• coss
• Cossack
• cosset
• cossie
• cost
• cost accountant
• cost accounting
• cost analysis
• cost cutting
• cost increase