The IUPAC name of compound

1. Identify the principal functional group: The $-OH$ group is the principal functional group, so the suffix is '-ol'.

2. Identify the parent chain/ring: The compound contains a five-membered carbon ring, so the parent name is cyclopentane.

3. Number the ring: Numbering starts from the carbon atom attached to the $-OH$ group (C-1) and proceeds in the direction that gives the lowest locant to the substituent. Thus, the carbon with the ethyl group gets position 2.

4. Identify substituents: There is an ethyl group ($-C_2H_5$) at position 2.

5. Combine the parts: 2-ethyl + cyclopentan + ol = 2-ethylcyclopentanol.

Answer: 2-Ethylcyclopentanol