Indulge comes from Latin indulgere (treat with undue favour, give rein to). A father indulging his child is thus pampering her and when one indulges one’s craving, one allows one’s cravings a free rein. From this indulgent gets the sense of permissive or tolerant (as in, indulgent grandparents).
Latin licere means to be permitted or allowed from which we get licence and licentious – which has taken on the negative connotation of sexually immoral or disrespectful towards social norms and standards.
Past participle of licere is licitus which gives us licit (permitted, legal, as in, a licit demand or by licit means) and illicit (illegal, improper – illicit trade or illicit relationship). Another related root, Old Frencg leisir, gives us English leisure (as in, you can do this at your leisure).
High Frequency Words for GRE, GMAT, SAT, CAT & Other Admission Tests*:
License, Licentious*, Licit, Illicit, Leisure