Being fuckly = when a person is ugly but still fuckable.
Or when a person has repulsive parts (body, character...) but not enough to be unerotic/unlovable.
Fuckly person: A person who is erotic in a matter of taste to some people. (often used in a negative way but not always)
It's a result from the combination of the words fuck and ugly and was earlier often used in meaning of a sexual act (one-night-stands) at which an ugly person profits from the charity alike intends of a "prettier" person.
Who said you're ugly? Hey, look at me. And I don't hear you complaining. You are still fuckly enough to make me go wild each and every day, babe.