The graph below from Intelligence, IQ and Perception, shows the various cognitive skills that are tested on the WAIS III IQ subtests.
You can see that vocabulary is a component of the verbal comprehension index, so a large vocabulary would certainly enhance an IQ score. However, there are many other important cognitive skills under the “Performance IQ” category on the top left. To estimate an IQ would require much more information from that side of the chart as well as from the “Working Memory Index” on the right side of the chart. However, a large vocabulary is a positive indicator for a high IQ, because there are some correlations among skills, however, much more information is needed to make a reasonable estimate of an IQ.
