Concept:
The adjective indolent refers to someone who avoids work or effort and prefers inactivity. It is commonly used to describe a lazy or idle person.
Step 1: Interpret the sentence.
The sentence states that the person's habits prevented him from maintaining a regular work routine.
Step 2: Understand the word meaning.
\[
\text{Indolent} = \text{lazy, idle, sluggish}
\]
Step 3: Evaluate the options.
• Foolish -- lacking wisdom.
• Lazy -- unwilling to work or exert effort.
• Benevolent -- kind and charitable.
• Active -- energetic and hardworking.
Step 4: Choose the synonym.
The correct synonym is lazy.
\[
\boxed{\text{Lazy}}
\]