The Hydrophilic/hydrophobic nature of the Cl-passivated Ge(001) surface is investigated directly by contact angle (CA) measurement and indirectly by growing nickel arachidate Langmuir-Blodgett (LB) films on the Cl-passivated Ge(001) surface. Passivation of Ge(001) surface by Cl atoms is confirmed by X-ray photoelectron spectroscopy measurement. CA measurements show that the Cl-passivated Ge(001) surface has intermediate wettability, i.e., the surface has intermediate hydrophilic/hydrophobic behavior. Structural information obtained from the deposited LB films by using X-ray reflectivity and atomic force microscopy analysis shows that the surface is homogeneous and hydrophilic (~ 85%), although very few effectively hydrophobic (~ 15%) regions are present. Structural study in molecular level thus helps to identify the surface nature in nanometer level, which is not possible by simple macroscopic CA measurement. Specific electrostatic and dispersive effects of Cl atoms are possibly responsible for such hydrophilic-like nature of the Cl-passivated Ge(001) surface.