重く

heavily; heavy

→ 重い
重 heavy + く Adverbial form
adjective Rare #37,457
heavily; heavy Describes something as having or feeling substantial physical weight; 重く is used before なる to mean “become heavy.”
JA: だんだん荷が重くなってきた。
EN: The load has gradually become heavier.
Forms of 重い

だんだん荷が重くなってきた。

It’s gradually becoming more than I can handle.

まったく重くなったな

It's gotten really heavy.

— ドライヴ (2011)

メイも重くなったなぁ。

Mei has put on weight too.

— となりのトトロ (1988)