What word was used with the meaning of "suicide" pre-1650s?

Solution 1:

There are several words (or phrases) that would have been used around that time:

• self-murder (examples: 1624, 1700)
• self-homicide (examples: 1616, 1644)
• self-killing (example: 1637)
• killing oneself (example: 1572)
• murdering oneself (example: 1638)

Solution 2:

In Middle English (the period preceding Early Modern English), there were several words that could be used to refer to suicide. Most frequently they were compound words or adaptations of words for murder:

• seolf-cwale (early Middle English only)
• āʒen-slaʒa (early Middle English only)
• man-sleing(e (also used for murder more generally)
• mortherer of self

Early Modern English speakers could use self- to create references to suicide. In addition to Laurel's examples, you have attested examples of:

• self-murther
• self-destruction
• self-violence (OED includes example from early 17th century)
• self-slaughter (OED again)