What does “SUBBED” mean?

In the case of a VCD, if a release is subbed, it usually means it has hard encoded subtitles burnt throughout the movie. These are generally in malaysian/chinese/thai etc, and sometimes there are two different languages, which can take up quite a large amount of the screen. SVCD supports switch able subtitles, so some DVDRips are released with switch able subs. This will be mentioned in the NFO file if included.

When a film has had a subbed release in the past, an “UNSUBBED” release may follow.

Source:
VCD Quality: FAQ