ru·pic·o·lous 
(r-pĭkə-ləs)
(r-pĭkə-ləs)adj.
Thriving among or inhabiting rocks.
[Latin rūpēs, rock (from ruptus, past participle of rumpere, to break; see reup- in the Appendix of Indo-European roots) + -COLOUS.]
- on the nose
- on the off chance
- on the onehand
- on the order of
- on the other hand
- on the outs
- on the part of
- on the prowl
- on the qui vive
- on the rack
- on the rag
- on-the-record
- on the right foot
- on the road
- on the rocks
- on the ropes
- on the run
- on the same wavelength
- on-the-scene
- on the shelf
- on the side
- on the sly
- on the spectrum
- on the spot
- on the square