The Collaborative International Dictionary of English v.0.48:

Lithesome \Lithe"some\ (l[imac][th]"s[u^]m), a. [See Lithe,
   a., and cf. Lissom.]
   Pliant; limber; flexible; supple; nimble; lissom.
   [1913 Webster] -- Lithe"some*ness, n.
   [1913 Webster]

WordNet (r) 3.0 (2006):

lithesome
    adj 1: moving and bending with ease [syn: lissome, lissom,
           lithe, lithesome, slender, supple, svelte,
           sylphlike]