This is really an intriguing piece, as might be expected from the hidden arms locker of the Major
While it may be 19th century, it seems done in the manner of 18th century items, and here I would note the European fascination with exotica, especially 'oriental' which covered pretty much Middle East, India and the Orient.
Note the Chinese style motif on the ferrule.
The undulating blade of course recalls the keris as noted.
Small swords of the 18th century often had such Oriental motif known as 'chinoserie'. There were even Chinese artisans in Europe working in shops in the mounting and hilt decoration of these swords.
The wavy blade to me suggests more of a male attribution , more of the kind of a knife that would be 'shown off' as the inclination of mens fashion in weaponry.
As far as I have known, I have only heard of muff pistols (from womens hand warmers) but not familiar with the dagger term.