Обожатель. Поклонник. Рачитель

The word obozhatel’ is derived from the verb obozhati in the end of the XVIII century.
Poklonnik is derived from the verbs pokloniti and/or poklonitisya. The word has acquired the meaning «follower, admirer» in the XVIII century.
The word rachitel’ is derived from the verb rachiti. In the modern language it has the meaning «he who eagerly cares for somebody/something» and is obsolete.