Hobbyhorse
['hɒbɪhɔːs]
Definition
(noun.) a topic to which one constantly reverts; 'don't get him started on his hobbyhorse'.
Inputed by Angie--From WordNet
Definition
(n.) A strong, active horse, of a middle size, said to have been originally from Ireland; an ambling nag.
(n.) A stick, often with the head or figure of a horse, on which boys make believe to ride.
(n.) A subject or plan upon which one is constantly setting off; a favorite and ever-recurring theme of discourse, thought, or effort; that which occupies one's attention unduly, or to the weariness of others; a ruling passion.
Editor: Philip