Willingly (4)
'willingly' is the definition.
(I've seen this before)
This is all the clue.
(Other definitions for readily that I've seen before include "Willingly, quickly" , "Promptly and without difficulty" , "Without difficulty or delay" , "Promptly; willingly" , "in a willing manner" .)
'willingly' is the definition.
(thesaurus)
This is the entire clue.
(Other definitions for happily that I've seen before include "Gladly" , "How everything should end?" .)
'willingly' is the definition.
(I've seen this before)
This is all the clue.
(Another definition for lief that I've seen is " In old usage, gladly or willingly - file away".)