Source : Webster's Revised Unabridged Dictionary (1913)

Lily-livered \Lil"y-liv`ered\ (-l[i^]v`[~e]rd), a.
   White-livered; cowardly.

Source : WordNet®

lily-livered
     adj : easily frightened [syn: {chicken}, {chickenhearted}, {white-livered},
            {yellow}, {yellow-bellied}]