con·quer
verb
1. overcome and take control of (a place or people) by use of military force.
"the Magyars conquered Hungary in the Middle Ages"
2. successfully overcome (a problem or weakness).
"a fear she never managed to conquer"
3. climb (a mountain) successfully.
"the second American to conquer Everest"
Well, Satan isn't a place or a people, and he isn't a mountain, so I assume we are to use the second definition: to successfully overcome. But what does it mean to overcome?
o·ver·come
verb
1. succeed in dealing with (a problem or difficulty).
"she worked hard to overcome her paralyzing shyness"
2. defeat (an opponent); prevail.
"without firing a shot they overcame the guards"
3. (of an emotion) overpower or overwhelm.
"she was obviously overcome with excitement"
And Satan isn't an emotion, and neither are we, so I assume are are to use the first to definitions: to succeed in dealing with him, and to defeat and prevail over him. And, one last one. What does it mean to prevail?
pre·vail
verb
1. prove more powerful than opposing forces; be victorious.
"it is hard for logic to prevail over emotion"
2. be widespread in a particular area at a particular time; be current.
"an atmosphere of crisis prevails"
3. persuade (someone) to do something.
"she was prevailed upon to give an account of her work"
We're not trying to convince Satan to do anything, but I find those first two definitions of prevail especially interesting. I find it encouraging that we can "prove more powerful" than Satan. He has had eons to gather his strength, whereas we have been alive for only a handful of decades. But there's part of the answer: We've been alive. Satan hasn't. Joseph Smith taught that "All beings who have bodies
have power over those who have not." Even just by being born, we have become more powerful than
Satan, and I find that fairly encouraging.
Furthermore, I cannot disregard the definition to "be widespread in a particular area at a particular time." This is also something that we are supposed to do. That's why we have missionaries. That's why we have temples all over the globe. We may not be trying to "overcome and take control of (a place or people) by use of military force," but we are certainly trying to spread out. And inasmuch as Satan has taken control of certain places and people, it would be prudent for us to drive him out and take that control back. So, maybe we are supposed to be conquerors. We have an interest in (re)taking territory that has been conquered by Satan, including our own.
The word "conquer" has a negative connotation these days, but by certain denotative definitions, conquering can be a good thing. Defeating Satan is certainly good, as retaking any region in which he has gained a foothold. We are to take the Gospel to all the world and to reduce Satan's power over it. If that makes us "conquerors," so be it.