【Lurk】 ,  【skulk】 ,  【slink】 ,  【sneak】  do not share a common denotation, but they are comparable because the major implication of each word is furtive action intended to escape the attention of others.

To  【lurk】 is to lie in wait (as in an ambush); the term sometimes implies only a place of concealment, but it often also suggests an evil intention, or quiet, stealthy movements, or a readiness to spring upon a victim.

To  【skulk】 is usually to move furtively but sometimes to 【lurk】 ; the word carries a stronger implication than the preceding word either of a sinister intention or of cowardice or fear.

To  【slink】 is to move stealthily or slyly in order not to attract attention.

To  【sneak】 is to get out of or into a place by slinking, or out of a difficulty by methods lacking in straightforwardness or definitely underhanded.