v.1. To eliminate some irregularities, roughness, or projections by stretching or spreading, so as to achieve a smooth surface or consistency: I had no time to iron my shirt, so I just ran my hands over it to smooth out the creases. If you're unhappy with the wrinkles around your eyes, surgery can smooth them out.
2. To rid something of obstructions, hindrances, or difficulties: Filing taxes was very confusing, but using online forms smoothes out the process. The assembly procedure is too complicated—we need to smooth it out.
3. To eliminate some obstructions, hindrances, or difficulties: I've been getting along better with my parents since we smoothed out our differences. Let me know what the problem is and I'll try to smooth it out.