最も荒涼たる日は一日中笑わなかった日である。

The most wasted day of all is that on which we have not laughed.

最(もっと)も荒涼(こうりょう)たる日(ひ)は一(いち)日中(にちちゅう)笑(わら)わなかった日(ひ)である。

Mottomo kōryōtaru hi wa ichi nichichū warawanakatta hi de aru.

最も (もっとも、もとも)

most; extremely

日 (ひ)

day; days; sun; sunshine; sunlight; case (esp. unfortunate); event

は (は)

topic marker particle; indicates contrast with another option (stated or unstated); adds emphasis

一 (いち)

one; best; first; foremost; beginning; start; bottom string (on a shamisen, etc.)

日中 (にっちゅう、ひなか)

daytime; during the day; Sino-Japanese

笑う (わらう)

to laugh; to smile; to sneer; to ridicule; to be dumbfounded; to be flabbergasted

だ (だ)

be; is; indicates past or completed action; indicates light imperative

或 (ある)

a certain ...; some ...

Readings: サイ、シュ、もっと.も、つま

Meanings: utmost, most, extreme

Readings: コウ、あら.い、あら-、あ.れる、あ.らす、 -あ.らし、すさ.む

Meanings: laid waste, rough, rude, wild

Readings: リョウ、すず.しい、すず.む、すず.やか、うす.い、ひや.す、まことに

Meanings: refreshing, nice and cool

Readings: ニチ、ジツ、ひ、 -び、 -か

Meanings: day, sun, Japan, counter for days

Readings: イチ、イツ、ひと-、ひと.つ

Meanings: one, one radical (no.1)

Readings: チュウ、なか、うち、あた.る

Meanings: in, inside, middle, mean, center

Readings: ショウ、わら.う、え.む

Meaning: laugh