What is the opposite word of entirely?

There isn't one single perfect opposite for "entirely." It depends on the context and what you're trying to convey. Here are some options:

For complete negation:

* Not at all

* In no way

* Absolutely not

* Not in the least

For partial negation:

* Partially

* In part

* Somewhat

* To some extent

For emphasizing a different part:

* Partially

* Only

* Solely

* Exclusively

For emphasizing a lack of completeness:

* Incomplete

* Unfinished

* Partial

* Limited

The best opposite will depend on the specific situation. For example, if you want to say the opposite of "entirely happy," you might say "not at all happy." But if you want to say the opposite of "entirely finished," you might say "partially finished."