Clue: Answer, as to an invitation: abbr.

Answer: RESP

Length: 4

---

Similar Clues:

• He answered "Yes" when Oprah asked him "In all seven of your Tour de France victories, did you ever take banned substances or blood-dope?" (LANCE with 5 letters)
• Tools for ESP researchers (whose symbols are found at the ends of the answers to the five asterisked clues) (ZENERCARDS with 10 letters)
• Unlike this answer (abbr.) (ACR with 3 letters)
• Horizontal, like this answer: abbr. (ACR with 3 letters)
• Subreddit abbr. for outrageous questions and answers (AMA with 3 letters)
• Ocean "crossing" this puzzle's four longest answers (abbr.) (ATL with 3 letters)
• Answer machine tones (BEEPS with 5 letters)
• This answer's place: Abbr. (CTR with 3 letters)
• Space-saving abbr. hidden in four puzzle answers (ETC with 3 letters)
• Country's total annual output: Abbr. (GNP with 3 letters)