beneficial
The definition for beneficial is "Helpful." Used in a sentence: there is no doubt that eating vegetables is beneficial to one's health.
benevolent
The definition for benevolent is "Kind, helpful." Used in a sentence: Sherman revealed his benevolent side when he offered to help Carter with his homework.
buffer
The definition for buffer is "Protective barrier." Used in a sentence: The dense trees acted as a buffer against the heavy rain.
ecstatic
The definition for ecstatic is "Overwhelmingly emotional." Used in a sentence: They were ecstatic when their team won the championship game in the last second.
polarize
The definition for polarize is "To break up into opposing groups." Used in a sentence: Thelma tended to polarize discussions rather than to encourage compromise.