feel bad, feel badly

People who use the expression feel badly are almost certainly using it incorrectly to mean feel bad. When they say they feel badly, they are mistakenly using feel as an action verb instead of as a linking verb.

Action verb

When the verb feel is used as an action verb, it expresses an action rather than an emotional state:

• The doctor felt the patient’s pulse.

As an action verb, feel can be modified by an adverb:

• The doctor anxiously felt the patient’s pulse.

In the expression feel badly, the adverb badly modifies the action verb feel. When people say I feel badly, they actually mean that they lack skill at feeling—in other words, they have a poor sense of touch. That is not the meaning most people intend!

Linking verb

As a linking verb, feel expresses an emotional state or a state of being:

• I feel happy.
• The pulse felt weak.

Linking verbs may be followed by adjectives that refer to the subject. Linking verbs connect or link these adjectives to the subject.

In the expression I feel bad, the linking verb feel links the adjective bad to the subject I. When people say I feel bad, they are expressing their emotional state. Since this is the meaning most people want to convey, the correct expression is feel bad, not feel badly.

Note: While correct, the expression feel bad is less formal in tone. In formal writing and speaking, you may prefer one of the equivalents listed in the left column of the table above.