Having a surface covered with or full of lumps. The mashed potatoes were lumpy and not smooth as expected.
Uneven or irregular in texture or consistency. The sauce turned out lumpy because it wasn't stirred properly.
Lacking grace or smoothness; awkward or clumsy in form, style, or movement. His lumpy handwriting was difficult to decipher.
(business, finance) Occurring in large, irregular amounts or at uneven intervals. The firm's cash flow was lumpy, with income arriving only after major projects were completed.