• oro bono,
• lro bono,
• -ro bono,
• 0ro bono,
• peo bono,
• pdo bono,
• pfo bono,
• pto bono,
• p5o bono,
• p4o bono,
• pri bono,
• prk bono,
• prl bono,
• prp bono,
• pr0 bono,
• pr9 bono,
• pro vono,
• pro nono,
• pro hono,
• pro gono

The adjective form of "pro bono" is "pro bono".

The plural form of "pro bono" is also "pro bono." It is an invariant plural noun, meaning it remains the same in both singular and plural usage.

The singular form of the word "pro bono" is "pro bono" itself. It is an adjective that describes something done or provided without charge, typically referring to legal services provided on a volunteer basis.