A intelligent ('buddhiman') man spends his time in the research and studies of literature ('Kaavya') and philosophy ('Shastras' like Veda Shastra, dharma shastra etc.). Or in other words the said subjects are means of his entertainment (He gets satisfaction due to the studies of 'kaavya' and philosophy).
In contrast a unintelligent ('Murkha') man gets satisfaction in bad habits like sleep (Laziness), quarrel or some type of addiction. Tatparya (Conclusion): In this subhaashita the subhaashitkar has in short advised the reader that how should one spend his/her time!! May be according to him a 'buddhiman' is a person who invests his time in order to get some thing 'valuable' and long lasting!!
A book says: Protect me from oil (Oily products which leave a mark on the page); Protect me from water; Also protect me from the loose binding; And after doing all this please do not hand me over to a 'Murkha' (unintelligent) person!!
The ears of a 'sajjan' (Honest/Good) person looks more good and pleasant hearing some knowledge ('Vidya') and not by the ear-rings ('Kundal'). Donating something more suites the hand than the bangles.
Like wise the body of a 'sajjan' person more suites by doing favours on others ('paropkar') than application of sandalwood's cream to itself.