Noun

(-)

Happiness.

*

Apt and pleasing style in writing, speech, etc.

Something that is either a source of happiness or particularly apt.

(Semiotics/semiology) Reproduction of a sign with fidelity. eg. "The quotation was rendered with felicity."

* {{quote-news, year=2007, date=August 7, author=Joshua Ferris, title=Table for Two, work=New York Times citation

, passage=The season’s main attraction, the felicities of the sun, dimmed in the light of our competition and our growing friendliness. }}

Noun

(-)

The property of being effective, of achieving results.

The effectiveness of the drug was well established.

The capacity or potential for achieving results.

*

The degree to which something achieves results.

He questioned the effectiveness of the treatment.

* 2013 , Phil McNulty, "[http://www.bbc.co.uk/sport/0/football/23830980]", BBC Sport , 1 September 2013:

United were having more possession but a sign of the effectiveness of Liverpool's defence was that it took the visitors 76 minutes to force Mignolet into serious action, when he dived to punch away a shot from substitute Nani.