unpredictable
adjective
1. not capable of being foretold
Similar word(s): uncertain, aleatory, capricious, freakish, episodic, occasional, unforeseeable
2. unknown in advance
- an unpredictable (or indeterminable) future
Similar word(s): indeterminable, undeterminable
3. not occurring at a regular rate or fixed intervals
noun
1. An unpredictable thing.