chain smoking

Short definition from Wiktionary

Adjective

1. 1
   Alternative form of chain-smoking.
2. 2
   Of or pertaining someone who chain-smokes.

Noun

1. 1
   Alternative form of chain-smoking.
2. 2
   The act or habit of smoking cigarettes continuously or frequently.

Verb

1. 1
   present participle of chain smoke
2. 2
   present participle and gerund of chain-smoke