Definition of Fiduciary capacity
One is said to act in a "fiduciary capacity” or to receive money or contract a debt in a "fiduciary capacity,” when the business which he transacts, or the money or property which he handles, is not his own or for his own benefit, but for the benefit of another person, as to whom he stands in a relation implying and necessitating great confidence and trust on the one part and a high degree of good faith on the other part. The term is not restricted to technical or express trusts, but includes also such offices or relations as those of an attorney at law, a guardian, executor, or broker, a director of a corporation, and a public officer.
That's the definition of Fiduciary capacity in Black's Law Dictionary 6th Edition. Courtesy of Cekhukum.com.