thicken
thick.en \'thik-*n\ \-(*-)nin\ \-(*-)n*r\ vb or thick.en.ing 1a: to make
thick, dense, or viscous in consistency 1b: to make close or compact 2:
to add to the depth or diameter of 3: to make inarticulate : BLUR {alcohol
~ed his spee ch} 1a: to become dense {the mist ~ed} 1b: to become
concentrated in numbers, mass, or frequency 2: to grow blurred or obscure
3: to grow broader or bulkier 4: to grow complicated or keen {the plot ~s}
- thick.en.er n
Webster's English Dictionary