Indefatigable

[Sarah]

incapable of being tired out; not yielding to fatigue; untiring.

[Julian]

[Tireless]; relentlessly working; unconquerable

A funny word that if said fast enough can be pronounced in - de - faggot - a - [ble]. Proper use denotes saying this word to [closet homosexuals] repeatedly until they catch on.

[Renato]

(of a person or their efforts) persisting tirelessly.