with considerable certainty; without much doubt
"He is probably out of the country"
"in all likelihood we are headed for war"
easy to believe on the basis of available evidence
"he talked plausibly before the committee"
"he will probably win the election"
In all likelihood.
"Since you left your umbrella behind, you will probably get wet if it starts raining later today."
In plain English: Probably means something is likely to happen but not completely certain.
"We will probably arrive home by six o'clock."
Usage: Use probably to express that something is likely to happen or be true based on available evidence, but not with complete certainty. Place it before the main verb or after the verb "to be" in most sentences.
The word probably comes from Middle English and is formed by adding the suffix "-ly" to probable. It entered usage as an adverb meaning "in a probable manner."