Split on either a space or a hyphen?

>>> import re
>>> text = "You think we did this un-thinkingly?"
>>> re.split(r'\s|-', text)
['You', 'think', 'we', 'did', 'this', 'un', 'thinkingly?']

As @larsmans noted, to split by multiple spaces/hyphens (emulating .split() with no arguments) used [...] for readability:

>>> re.split(r'[\s-]+', text)
['You', 'think', 'we', 'did', 'this', 'un', 'thinkingly?']

Without regex (regex is the most straightforward option in this case):

>>> [y for x in text.split() for y in x.split('-')]
['You', 'think', 'we', 'did', 'this', 'un', 'thinkingly?']

Actually the answer by @Elazar without regex is quite straightforward as well (I would still vouch for regex though)

A regex is far easier and better, but if you're staunchly opposed to using one:

import itertools

itertools.chain.from_iterable((i.split(" ") for i in myStr.split("-")))

If your pattern is simple enough for one (or maybe two) replace, use it:

mystr.replace('-', ' ').split(' ')

Otherwise, use RE as suggested by @jamylak.