slink vs snail's pace

slink

• A furtive sneaking motion. 

• The meat of such a prematurely born animal. 

• A thievish fellow; a sneak. 

• The young of an animal when born prematurely, especially a calf. 

• Thin; lean 

• To sneak about furtively. 

• To give birth to an animal prematurely. 

snail's pace

• A very slow pace.