No. Although the names applied to God signify one thing, they are not synonymous because they signify that one thing under many and different aspects.
Synonymous terms, however, signify one thing under one aspect.
The many aspects of these non-synonymous names, when applied to God, are not empty and vain, for there corresponds to all of them one simple reality, but represented by them in a manifold and imperfect manner.
The idea signified by the name is the conception in the intellect of the thing signified by the name. But our intellect, since it knows God from creatures, in order to understand God, forms conceptions proportional to the perfections flowing from God to creatures.