diminishing
adj. B2 Upper Intermediate US //dɪˈmɪnɪʃɪŋ// UK //dɪmˈɪnɪʃɪŋ// di·min·ish·ing
adj. getting smaller, weaker, or less important over time. You use this when something is slowly losing its power or value.
adj. decreasing in size, amount, intensity, or importance. Typically used attributively before a noun or predicatively after a linking verb.
The noise level is diminishing every hour.
The company's market share is diminishing due to new competitors.
As the initial excitement faded, the diminishing returns on their investment became painfully clear to the board members.
Usage
Often used with 'returns', 'light', or 'interest'.