Busier

actively and attentively engaged in work or a pastime:
busy with her work.
not at leisure; otherwise engaged:
He couldn’t see any visitors because he was busy.
full of or characterized by activity:
a busy life.
(of a telephone line) in use by a party or parties and not immediately accessible.
officious; meddlesome; prying.
ornate, disparate, or clashing in design or colors; cluttered with small, unharmonious details; fussy:
The rug is too busy for this room.
to keep occupied; make or keep busy:
In summer, he busied himself keeping the lawn in order.
Contemporary Examples

As the Key Battle Looms, a Report from Ukraine’s Front Lines Jamie Dettmer August 12, 2014
Existing Home Sales Rise in July Daniel Gross August 21, 2012
Exclusive: Inside a Cop-Killer’s Final Hours Michael Daly December 30, 2014

Historical Examples

Comrade Yetta Albert Edwards
Simon Dale Anthony Hope
New Faces Myra Kelly
Solander’s Radio Tomb Ellis Parker Butler
Sunshine Sketches of a Little Town Stephen Leacock
The Poor Scholar William Carleton
Pencillings by the Way N. Parker Willis

adjective busier, busiest
actively or fully engaged; occupied
crowded with or characterized by activity: a busy day
(mainly US & Canadian) (of a room, telephone line, etc) in use; engaged
overcrowded with detail: a busy painting
meddlesome; inquisitive; prying
verb busies, busying, busied
(transitive) to make or keep (someone, esp oneself) busy; occupy
adj.
v.

busy as a beaver
busy work