Insincere means saying warm things you do not feel. An insincere apology, insincere praise, sounded insincere.
It is the charge levelled at the words rather than the act — an insincere apology may say everything right and still fail, because what is missing is the feeling behind it. People detect it from timing and tone more than from wording. Note sincere; and that the Latin sincerus means pure or unmixed.
1adjectiveinsincereSaying warm things you do not feel.
“His praise sounded insincere, as if somebody had told him to say something nice.”
insincere is a quality of falseness.
Latin insincerus is in- plus sincerus, pure or whole. The popular story that sincere means without wax is not true.
Latin
insincerus
English, today
insincere
From Latin insincerus.
Etymology from Wiktionary, CC BY-SA