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

• four-flusher
• four-footed
• four-footed butterfly
• four-four time
• four-hitter
• four-hundredth
• Mumbai
• mumble
• mumble-the-peg
• mumbler
• mumblety-peg
• mumbling
• mumbo jumbo
• mumification necrosis
• mummer
• mummery
• mummichog
• mummification
• mummify
• mummy
• mummy-brown
• mumps
• mumpsimus
• mumsy
• mun