The Sun and Mercury in the same sign. The handbooks state no orb condition, but Mercury within 14 degrees of the Sun (12 when retrograde) is combust, so the strongest form has Mercury in the Sun's sign beyond the combustion orb.
Fruit
Intelligence, learning, administrative skill, eloquence and fame: a person who is clever in the world's terms and recognised for it. The yoga is read as a mark of sharp intellect rather than of wealth or of virtue.
Meaning
Mercury never travels far from the Sun, so this combination occurs in roughly a third of all charts, and its strength turns almost entirely on how far Mercury stands from the Sun. It is the standard combination for a scholar, an administrator or a writer.