The Various Meanings of "Outweigh" in English and How to Express Them in Spanish
'Outweigh' in Spanish - It May All Come Down to "Trumping"
If one is speaking literally, then the idea of to outweigh is expressed in Spanish with a comparative: pesar más que or pesar menos que:
Juan pesa más que Tomás (Juan outweighs Tomás).
This phrase can be applied metaphorically to speak of more intellectual, moral or abstract ideas, but there are more interesting verbs to be found. Learning to use such verbs and phrases as superar, vencer, ser más/menos importante que and de mayor importancia/peso will enrich your speech. None of them are particularly difficult or unusual verbs. Superar and vencer, while not exact translations of outweigh, show that something overcame something else.
Los esfuerzos de los investigadores superaron los obstáculos (The researchers' efforts overcame the obstacles). Here, the sense of outweigh is conveyed by the fact that on the one hand, there were obstacles but that the efforts more than counter-weighed or counter-balanced them.
Sus argumentos vencieron las opiniones contrarias (His arguments vanquished the contrary opinions).
The other phrases offered as solutions to the problem of to outweigh offer considerable flexibility, so long as one has enough skill handling comparatives of inequality.
Las ventajas de la ciudad son más importantes que las desventajas (The advantages of a city are more important than the disadvantages).
Note how this same idea can be expressed using superar or vencer, hence the value of superar as a solution to outweigh:
Las ventajas de la ciudad superan/vencen las desventajas.
Another useful expression that has some affinity to the concept of outweighing is poner fin a la duda or the simple verb convencer.
Después de varias horas de discusiones, Juan me convenció que su plan funcionaría (After several hours of discussion, Juan convinced me that his plan would work).
Juan puso fin a mis dudas (Juan put an end to my doubts).