Frequency: The word is one of the 3000 most common words in English.
1.
Entirely means completely and not just partly.
...an ~ new approach...
Fraud is an ~ different matter...
Their price depended almost ~ on their scarcity...
= completely, totally
ADV: ADV adj, ADV with v, ADV with cl/group
2.
Entirely is also used to emphasize what you are saying.
I agree ~...
Oh, the whole episode was ~ his fault.
ADV: ADV with v, ADV group emphasis