Retaining refers to the process of keeping or holding onto something. Synonyms for this word include preserving, maintaining, upholding, sustaining, and conserving. Preserving means to keep or protect something from damage or decay. Maintaining refers to the act of continuing to hold onto or keeping something in good condition. Upholding also suggests the act of maintaining or supporting something, often a belief or principle. Sustaining is similar but implies the act of providing support or nourishment to something. Lastly, conserving suggests the act of maintaining or preserving something for future use or enjoyment. These synonyms all relate to the idea of keeping or holding onto something in one way or another.