(A proofreader's note regarding “compel” and “impel”)

“Compel” and “impel” are two similar performers

That share a connection to “urge.”

While both verbs relate to a pushing to action,

“Compel” has more senses to splurge.

The most common sense of “compel” that we find

Is “to forcefully urge to an act.”

Included as well, “irresistibly” factors;

It hints at coercion, in fact.

“To cause to occur or to happen/accomplish

With force or great pressure applied” 

Is one other sense that is frequently lent;

A restriction of choice is implied.

“Impel,” quite in contrast, is more motivational

In one sense that's like to “compel”:

“To drive or to urge/motivate into action

By strong moral pressure upheld.”

The force urging action is often internal

With this the more common of meanings;

A deeply embedded emotion or preference 

Is usually driving its leanings.

“Impel” in its usage may also be physical,

A second sense clearly defined.

It means to “propel,” but is unlike “compel” 

Where the physical sense is unkind.

“Compelled to respond in his box near the judge,

He was fighting an impulse to flee.

Alas, though, his conscience was much more impelling;

It left him impelled to agree.”