Two for Pen:
Hen - Usally refers to a female bird, especially a domestic fowl. Can also be a domestic fowl of either sex.
Den - A wild animal's lair or habitation; (of a wild animal) live in or retreat to a den.
Two for Clock:
Mock - Tease or laugh at in a scornful or contemptuous manner; not authentic or real, but without the intention to deceive.
Lock - A mechanism for keeping a door, lid, etc., fastened typically operated only by a key of a particular form; a short confined section of a canal or other waterway in which the water level can be changed by the use of gates and sluices, used for raising and lowering vessels between two gates; fasten or secure (something) with a lock; restrict access to the full functionality or data of (a computer, mobile phone, file, etc.), especially by requiring a user to verify their identity with a passcode or other form of authentication.
Other Words You Could Use:
Pen - Men, Phelgm, Then, When, Ten, Zen
Clock - Talk, Stalk, Dock, Crocs, Rock, Shock, Knock, Chalk, Bach, Block, Sock, Interlock, Unlock, Jock, Tock, Tic-tock, Bangkok,