From self- +‎ supporting.

self-supporting (comparative more self-supporting, superlative most self-supporting)

1. Characterized by self-support.

   Synonym: self-supported

   • 1963 August, “British Railways in 1962—The Annual Report”, in Modern Railways, pages 119–120:

     With a self-supporting body and without separate underframe, this design offers scope for improved sound insulation; […].

   • 1934, Ernest Bramah, The Bravo of London:

     Now that's really very kind and generous of you; very thoughtful indeed, Mr. Dixson. Yes, we have a variety of useful organisations in the parish, and most of them, as you tactfully suggest, are not by any means self-supporting.

• “self-supporting”, in Lexico, Dictionary.com; Oxford University Press, 2019–2022.