1. Godan verb with 'u' ending, Transitive verb

   to finish; to stop; to end; to put an end to; to bring to a close

   Usually written using kana alone

   買い物を済ませてしまったら電話します。

2. to close (a business, etc.); to close down; to shut down; to shut up

   Usually written using kana alone

3. to put away; to put back; to keep; to store

   Usually written using kana alone

4. Auxiliary verb, Godan verb with 'u' ending

   to do completely; to finish

   Usually written using kana aloneafter the -te form of a verb

5. to do accidentally; to do without meaning to; to happen to do; to end up ...

   Usually written using kana aloneafter the -te form of a verb

Also written 終う【しまう】shimau、了う【しまう】shimau、蔵う【しまう】shimau